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HomeMy WebLinkAbout801192.tiff CITY OF GREELEY, COLORADO WASTEWATER FACILITIES PLAN I WELD COUNTY, COLORADO SPECIAL USE PERMIT APPLICATION LAND APPLICATION TREATMENT FACILITY A Professional Corporation MIX Engineers Architects Planners 2021 Clubhouse Drive Greeley,Colorado 60631 SPECIAL USE PERMIT APPLICATION Weld County Department of Planning Services 915 - 10th Street Greeley , Colorado 80631 PHONE : 356-4000 Ext. 400 FOR PLANNING DEPARTMENT USE ONLY : Permit Fee : Case Number : Recording Fee : App . Checked by : Receipt No. : TO BE COMPLETED BY APPLICANT IN ACCORDANCE WITH PROCEDURAL GUIDE REQUIRE- MENTS : Print or type only , except for necessary signatures . I , (we) the undersigned , hereby request a hearing before the Weld County Planning Commission concerning a proposed Special Use Permit for the following described unincorporated area of Weld County : LEGAL DESCRIPTION of contiguous property owned upon which Special Use Permit is proposed : — • All of Sections 5 and 6 in T5N, R63W, and all of Sections 15, 21, 22•, 27, 28, 29, 31, 32, and 33 in T6N, R63W 11 Sections x 640 = 7,040 Acres • LEGAL DESCRIPTION OF SPECIAL USE PERMIT AREA: Same as above STREET LOCATION : Weld Co. Rds. 62 and 61 (3 miles E. of cm) ZONE : Agricultural PROPOSED USE : Wastewater Treatment Facility • FEE OWNERS OF AREA PROPOSED FOR SPECIAL USE : • NAME : See attached sheet ADDRESS : - TEL : NAME : ADDRESS : TEL : NAME: ADDRESS : TEL : I hereby depose and state under the penalties of perjury that all state- ments , proposals and/or plans submitted with or contained within this application are true and correct to the best of my knowledge . COUNTY OF WELD ) STATE OF COLORADO ) Signature : Owner or Authorized Agent Subscribed ans sworn to before me this day of , 19` SEAL Notary -Public My commission expires : _ _ llNAME ADDRESS TELEPHONE A. Bruce & Jackson B. Wells Jackson B. Wells 352-2952 Gill , Colorado 80624 State Board of Land 1313 Sherman Suite 620 Commissioners Denver, Colorado 80203 839-3454 Carroll & Arlene Bishop 32138 Weld Co. Rd. 68 352-8048 Gill , Colorado 80624 Theodore L. Nieman 222 + S. Ogden Street Denver, Colorado 80210 Jackson B. & Lillian M. Wells Gill , Colorado 80624 352-2952 Jacob, Jr. & Shirley L. Rt. 1 Box 24 Miller Gill , Colorado 80624 352-1749 —._ s{•.Ay. - , - , t� -� _ - ip.' .-..---- _ __ - , .)` AW A — .v"�?rT.-ss .asaY _ - •S - • . ,Irvil , 4 i,,,"'"•-. " Pr, r ___..,--------s7:;ru - - --_____ At mss% y -¢ - 0,l 1' - . s, �„. ,� c.....:,..._2.,j..--.„--.....,• •a,Niz_v+• 0 •f•-•.,..,-.'` r �q •' 1e �"' I ..m_ �-iU ,;,,z,--)r`,"1 r.. ."'" `..,s�� Cosh. 7 ie w �e� ,.5.J a lMJ�S .��ila�7ne, \�'il � tA._.s..ra: �� •- "" .AA4v 1 G'7,iz.,, GREELEY CIVIC CENTER • GREELEY COLORADO 80631 October 2 , 1980 PHONE ,303, 353-6123 Weld County Planning Commission Weld County Court House 919 - 10th Street Greeley, Colorado Dear Commission Members : Pursuant to discussions between the Weld County Attorney ' s Office, the Law Department of the City of Greeley, and the 201 Project team, the City of Greeley submits the attached application for a Special Use Permit . As you will note from the information contained therein, the City does not currently own the property required for the construction of this treat- ment facility. Therefore, we are requesting that this applica- tion be approved conditioned upon the acquisition of that property, through purchase or condemnation, prior to construction of the project . • This type of request is necessitated by conflicts in local regulations and federal funding requirements . The Environmental Protection Agency will not approve and release any funds for the purchase of land to be used in this project until all local requirements are met . One of those requirements for the Step III Grant is the Special Use Permit for which we are now applying . If we must acquire the subject property to obtain the Permit , the Federal Government will not reimburse the City for any of those f expenditures . Therefore , we request the issuance of a Special Use Permit with the condition that we obtain a legal interest in the property prior to commencing work on the project . This will enable us to obtain necessary funds for purchase from the E. P .A. Thank you for your time and consideration in this matter . Very truly s , v`i' o� . D ' a co City Attor ey jk i "A COMMUNITY OF PROGRESS" • INTRODUCTION This report includes information required by Weld County in order to make application for a Weld County Special Use Permit. The "Procedural Guide for Special Use Permit Application Weld County Planning Commission" was followed in assembling the information. The report is presented in three parts. Part I is 'entitled Project Background and Information. It includes miscellaneous information as required for the special use permit in additign to providing' the reader with a background of the project. Part II is entitled Bedrock Geology Investigation and was prepared by ESA Geotechnical Consultants. Part liIII, which is called Report of a Geotechnical Investigation, was prepared by Empire Laboratories, Inc. The contents of Parts II and III are supplemental to the extensive soils investigations contained in Volumes I and II of the Greeley Wastewater Facility Plan. One copy of the complete Greeley Wastewater Facility Plan, Volumes I, II, and III, has been submitted to the Weld County Planning Department to be kept on file. Information on the soils of the treatment site is included throughout the three volumes of the Facility Plan. This condensed soils information provides a representative sample of the overall soils investiga- tions while eliminating the need to review the entire Facility Plan. II II 1M PART I PROJECT BACKGROUND AND INFORMATION • r II PART I TABLE OF CONTENT S Page PROJECT BACKGROUND 1 PROJECT APPROACH 2 '' THE DECISION MAKING PROCESS 3 THE .PREFERRED ALTERNATIVE 4 II General Information 4 Design Development 6 Citizens Advisory Committee Alternative (Site 4) 8 DESCRIPTION OF THE PROPOSED OPERATION SITE I 8 ENVIRONMENTAL IMPACTS 10 - Surface Water Quality 10 Groundwater Quality 10 Public Health 11 Odor 11 Visual 12 ill Agriculture 12 Land Use 13 WATER SUPPLY 13 ACCESS ROADS 14 • PROPERTY OWNERSHIP 15 , 1 i , E PROJECT BACKGROUND Initial planning for the upgrading and expansion of Greeley' s Wastewater Treatment facilities was begun in 1972. The engineering firm of Wright- McLaughlin Engineers was retained to prepare a Facility Plan which would llidentify alternative long term solutions for the treatment and disposal of Greeley's wastewater. This study was completed in 1975. After completion of IIthis study, the Greeley Water Board recommended that the City Council proceed with the design and construction of a new "mechanical" treatment plant located at the "Delta" site east of the city. The plan also called for the rehabilita- tion of the existing First Avenue Plant which would continue in operation until approximately 1990. A great deal of controversy- surrounded the adoption of this plan. Organized opposition, consisting of residents and landowners living in east Greeley and the Delta site areas, aggressively opposed the plan to construct lla wastewater treatment plant in that location. The Environmental Protection Agency, partially as a result of this opposition, required the City of Greeley llto undertake an Environmental Impact Assessment of the proposed plant along with a complete Environmental Impact Statement. Ultimately, the locally adopted plan was accepted by the Colorado Water Quality Control Commission and the Environmental Protection Agency. However, certain area residents continued to actively oppose the project. Complete information regarding the initial Facility Planning Process and the Environmental Impact Statement is contained within the following documents which are on file at the administrative offices of the City of Greeley, the Colorado Water Quality Control Commission, and the Environmental Protection Agency. ll ° Facilities Plan Report, Sanitary Sewage System for the Greeley Region Weld County, Colorado ** Part One, Basic Information and Analysis - 1 - F ** Part Two, Alternative Plan Formulation, Master Plan Initial Program • ** Part Three, Public Participation and Supplemental Information ° Final Environmental Impact Statement Greeley Region Wastewater Management Program IIAfter receiving approval to proceed with the plan to upgrade First Avenue and construct the First Phase of a new plant in the Delta area, an application _ for funding assistance for design of the facilities was submitted to the Water ilQuality Control Commission and EPA. This application was approved and the City then retained the firm of CH2M Hill , Inc. to complete the design of the project . During the preliminary design, new construction cost estimates were prepared which indicated that the total construction cost of the proposed facilities would be in the range of 23 to 26 million dollars. The adoption of the original plan was based upon estimates of construction costs in the range of eight to nine million dollars. This fact, along with a new national emphasis on land treatment and "non-mechanical" treatment systems, together IIwith continued opposition from residents of the "Delta" plant area, caused the Greeley Staff, Water Board, and City Council to re-evaluate the desirability of proceeding with the proposed plan. As a result of this re-evaluation, the City decided to study several additional alternatives which had not been considered in the origianl Facility Plan. PROJECT APPROACH The planning process associated with the preparation of the original Facility Plan resulted in the resolution of many issues related to the planning of future wastewater treatment facilities to serve the community. Analysis of IIfactors such as population, land use, waste characteristics, service areas, infiltration, etc. is unaffected by the reconsideration of the method of - 2 - i treatment and ultimate disposal of the treated wastewater. Consequently, additional studies were limited to only an evaluation of various methods of treatment and disposal of wastewater not evaluated in the original Facility Plan. The newly developed alternatives were then compared to the originally adopted plan and a decision was made to follow a new course of action. During the analysis of the newly developed alternatives, the Environmental Protection Agency indicated the need to revise the original Environmental Impact Statement to consider the newly developed alternates. As a result, the City of Greeley retained URS, an environmental consulting firm, to complete the EIS revision. THE DECISION MAKING PROCESS • The implementation of any plan will affect many individuals and interests ranging from those directly affected such as property owners to those indirectly affected such as local businessmen, environmental interests, etc. Because so many individuals and groups are affected in one way or another, it is extremely important that all parties have the opportunity to express their concerns/ opinions and that this information be made available to those individuals who must make the ultimate decision. The initial Facility Planning and Environmental Impact processes provided the opportunity for substantial input from individuals and/or affected interests through public hearings, meetings and formally organized advisory groups. In addition to the re-evaluation of the treatment aspects of the plan, every attempt was made to gather the opinions, concerns and ideas which the affected public had regarding this project. This information has been documented and considered much in the same way as other data related to the alternates under study. All such information was available prior to the time the decision was made by the various public officials responsible for the project' s ultimate completion. - 3 - After the various treatment alternates were identified, each was then subjected to a thorough technical analysis, the results of which are contained within two documents, "Wastewater Facilities Planning Report No. I, Vol . 1 and Vol . II, 1979". Simultaneously, numerous individuals, organizations, and agencies were contacted to inform them of the present work and to receive their comments regarding the project. After adequate time had elapsed for the review of this information, additional public meetings as well as a Public Hearing were held to hear the views of all interested parties. In addition, the Environmental Consultant, as part of the requirements of the EIS process, held other public meetings and a formal hearing on the draft EIS amendment. After review of the technical analysis, public input, and environmental analysis, the Greeley Water Board recommended to the City Council a future course of action. Following adoption of a plan at the local level , the plan was then submitted to the Colorado Water Quality Control Commission for their approval . Finally, the Environmental Protection Agency must also approve the plan before design and construction can proceed. Throughout this process, numerous other local , state and federal agencies will be reviewing the plan and submitting comments to the agencies. having decision making responsibilities. THE PREFERRED ALTERNATIVE General Information After a thorough review of all available information which included technical data, the environmental analysis, input from the public, and engineering staff recommendations, the Greeley Water and Sewer Board and the City Council voted to proceed with the implementation of the Land Application Alternative. This alternative as originally developed, is fully described in Chapters III and IV of Vol . 1 and Vol . II of the "Wastewater Facilities Planning Report No. 1." - 4 - In accordance with the requirements for public participation set forth by EPA, a Citizens Advisory Committee was appointed by the City Co uncil to lassist in the development and evaluation of the project. This group strongly supports implementation of the Land Application Alternative in concept but IIstrongly recommended that the facility be located approximately four miles d southeast of the originally proposed site. The basis of this recommendation was that by changing the location, all of the expressed concerns relating to negative environmental impacts would be eliminated. Specific concerns with locating the facility at Site I (the original proposed location) are documented in the record of testimony from the EIS Public Hearing and in the Committee report to the City. , I • Due to the concerns expressed regarding the proposed location of the Land Application system, the Greeley City Council authorized the submission of a grant application to the Water Quality Control Commission for additional evaluations of Site I. This application was approved by the Commission at its regular meeting on June 2nd, 1980. On June 20th, a grant offer was made by EPA for the additional evaluations of Site I . The primary purpose for the additional study was to further investigate the physical characteristics of the soil and underlying geological features in IIorder to answer questions raised by City Council, Water Board ana the Citizens Advisory Committee concerning the suitability of Site I. The underlying purpose was to increase the degree of reliability of the data used to select the site for the project. A description of the soils and geological studies undertaken and the results of those studies is included in this report. Following is a summary of the conclusions reached by the Project Team regarding the suitability of Site I for the proposed treatment facility: - 5 - 1. Site I is the most desirable location of the project from the standpoint of cost, management of water rights, and physical conditions of the site. 2. Underlying geology (bedrock formations) will not permit infiltration of any significant quantities of treated wastewater into lower formations. 3. Overburden materials (surface to bedrock) are capable of accepting applications at originally estimated rates. 4. The proposed system will not adversely affect farmlands to the west of the site by raising the groundwater table as has been suggested by property owners in the area. 5. Water passing through the crop root zone and not consumed by the crops will be recaptured by the use of interceptor drains, ditches, and wells. • 6. Water rights management is greatly simplified at Site I since return flows can be discharged to Crow Creek and/or the Ogilvy Ditch. Based upon the results of all studies, the Greeley City Council , on August 11, 1980 selected the Land Application Alternative located at Site I as the preferred alternative. Design Development Four conceptual alternatives were originally selected for complete design development and analysis. These included the following: 1. Treatment at the Delta Site using a conventional "Mechanical" treatment facility. - 6 - t 2. Treatment and Discharge to Crow Creek using a "non-mechanical" ' (aerated lagoon) treatment system. 3. Treatment and Discharge to Crow Creek during the winter months with discharge to the Ogilvy Ditch during the irrigation season. 4. Treatment utilizing a conventional Land Application System. Preliminary design development resulted in the identification of numerous - ways of developing the alternative system concepts which would satisfy the basic design requirements of the project. Chapters III and IV of Vol . I of the "Wastewater Facilities Planning Report" contain the detailed information relative to all of the sub-alternatives which were evaluated. The Land Application Alternative at Site I was selected from a total of eighty-seven . . different alternative systems which were developed and evaluated. The basic treatment components of the Land Application System at Site I include a four day detention aerated lagoon, storage reservoir, and center pivot irrigation sprinklers. An extensive underdrain system will be installed in the areas irrigated by the center pivots in order to reclaim the treated wastewater for discharge into Crow Creek. Early in the evaluations, several locations were designated as potential sites for land application treatment and storage systems as described above. These sites were first evaluated to determine whether a winter storage reser- voir of adequate size could be constructed at a reasonable cost. It is also advantageous to locate the reservoir near the most desirable application areas. From these studies, Site I was determined to be the most feasible of the reservoir sites from engineering, financial and water rights management aspects. The topography of Site I is well suited for the economical construc- tion of a reservoir of adequate size. Site I is closer to the City than other sites which will result in lower costs for construction and operation of the required pumping station and transmission lines. - 7 - { I .1 I \ -r ',-ti 't - j '' - IIIt '> 1 Y / ''(.',` p ` u t f J R•l II '-. t , 0.a- r{" , u I , I 'i• I S ,i _ �, ,r ..4't w 'r' e ' ',s ' f i .J �%N.i \ I 4�1 f• I ! -, / I � �' , I I _ J �; �, p_-^, r n1 i s. )1"Li.,._ .\ , 1 `-•. T --`——i �-- —— =I`_-- :� —. —+mil -. ...r-1._•-4}.-++ . , -:� / -,++, 7,- ,:,, ,.-,f+-.(, - - - _� - ... -�411sa�4,rr� ` a iii,�� t„0,01 t .I.JI1 N ., ---' '''t / '1... II , rte y l' ti 'r r S � ltiiiiil—...1�►\ i - � ae► ■.iii■■rfit■ r t I -5---- = , _ ;A: ' • -f.; ._-- •�. ' Ii�i�d�i�• •n►1i7■i■. s__ - _ i yaiiii�=ice■■!! rr •�} T l,_ —='.r M \i i■�' \iii "t li �'r' .!� '- IF 1 a F� ' ` : Y!■t. x - ;4. O •-)k-..,- ,� �' o :+� ' - Wit' r�'.,, - - ,FT•- - -I 'I `, - 5- +.. k.,-..)• r A Y tl . I • • l s ,, a lii i t. a } 4 1�, r ' '' .! I' ���LLL t`fir M �j /, '' ,e �. I0 is V. . ,,,-.'..,, .,'ilt /,mow } '+? • "I •ay► --r Ja �f.p '1 ' •-"•• . 51 -i ` I POTENTIAL RESERVOIR SITES,, Citizens Advisory Committee Alternative (Site 4) . As previously discussed, the Citizens Advisory Committee recommended to the Greeley City Council consideration of the development of the Land Applica- tion System approximately 3-1/2 miles southeast of the originally proposed location. As a result of this request, a preliminary engineering analysis was made of this proposal . A preliminary analysis of this proposal indicates that from an engineer- ing viewpoint, the system can be successfully developed in this location. However, due to the substantially higher project costs and water rights ' management issues, Site I was selected as the best location for the project. DESCRIPTION OF THE PROPOSED OPERATION AT SITE I The information which follows is based on preliminary engineering studies which were summarized in Volumes I, II and III of the "Wastewater Facilities Plan" for the City of Greeley. During final design of the project, a more detailed study of the treatment system will be made, and the results of the preliminary studies will be subject to modification. The layout of the treatment components at Site I is shown on the special use drawings in concept only, and the exact location of the lagoon system, piping and center, pivot sprinklers will be determined in final design. The reservoir location is somewhat fixed due to its dependence on the existing topography of the site. i It is not intended that the exact layout of the site as presented be made a requirement of the special use permit. Wastewater will be transported to the treatment site by means of a proposed pumping station at the "Delta" site, and a transmission system extending from the "Delta" to the lagoon site. The aerated lagoons will be the first step in the treatment process, and a minimum of two lagoon cells will be constructed. Wastewater will flow from the lagoon system into the storage - 8 - 1 reservoir where further treatment takes place. The treatment system has a built-in flexibility• at this point. Wastewater can be discharged directly to Crow Creek from the reservoir if only a secondary level of treatment is desired. However, an advanced level of treatment can be obtained by using effluent from the reservoir to irrigate crops through the center pivot sprink- ling system. Nutrients are removed from the wastewater by the crops and the unused portion of the wastewater is then collected in the underdrain system for discharge into Crow Creek. The lagoons are proposed to be sized for 4 day detention prior to releas- ing the wastewater into the storage reservoir. Surface aerators will be used to provide proper aeration of the wastewater which should be sufficient to prevent undesirable odors or appearance in the storage reservoir. Sludge will accumulate in the lagoons as a result of treatment of the raw sewage. The lagoons will require sludge removal every two to three years. The sludge will be of a thick but liquid consistency and removal is accom- plished by pumping or scooping with a loader. The sand hills within the treatment site provide an excellent natural drying bed for the removed sludge. Proper operation of the lagoons will produce a sludge that is stable and odor-free thus reducing 'the potential for health hazards during handling. The staff required for operation of the lagoon system is estimated at nine employees. This number includes a superintendent, lab technicians, operators and maintenance men. The majority of these employees are expected to work during the day although operators will be at the plant during evening and night shifts as well . The storage reservoir will require a maximum of two employees during •the day primarily for maintenance purposes. It is not yet known whether the City will own or merely lease the land required for the center pivot irrigation system. The farming operation itself may be leased out to local farmers who would then be responsible for their own - 9 - labor requirements. The number of workers required is also dependent on the type of crop to be grown, and at least two crops, alfalfa and corn, are being considered. The number of City employees could range from zero to ten depenu- ing on the ownership or leasing agreements . A reasonable estimate of the manpower requirements for the farming operation can be mane based on 3U0 acres per man. With modern equipment and center pivot sprinklers for irrigation, a total of 10 farmers would be needed based on 300 acres per farmer. ENVIRONMENTAL IMPACTS The following information has been taken from the Draft Environmental Impact Statement which was prepared for the City of Greeley Wastewater Treat- ment Alternatives. Only the information for the Land Application System at Site I is included below. Surface Water Quality The point of discharge of Greeley' s wastewater effluent would be removed from the Cache la Poudre River. This would improve the water quality in the river. The discharge would be made into Crow Creek between March and October and is expected to improve the water quality of both Crow Creek and the Platte due to the high quality of the effluent. The overall effect of the Land Application System at Site I on surface water quality is beneficial . Groundwater Quality Soils in the reservoir site have high permeabilities and so seepage is expected from the reservoir. However, an interception ditch will be con- structed around the perimeter of the reservoir to capture this seepage water. This water will either be recycled to the reservoir, or discharged to Crow Creek depending on its quality. The reservoir will also be partially lined to reduce this seepage. The lagoons are to be lined with an impervious material, so no groundwater impacts will occur due to raw or partially treated wastewater. - 10 - In the application site, the underdrains will capture the effluent which percolates through the soil . Consequently, minimal impacts to groundwater at the treatment site are expected. Public Health Public health risk associated with the land application system is the potential public exposure to the effluent during irrigation. Wind blown effluent from spray irrigation has been shown to transmit pathogens. Conse- quently, buffer zones surrounding the land application site would be required. The size of these buffers currently has not been determined. An evaluation of wind velocity, and residential dwelling locations will be made during the . final design stage in order to properly size the buffer zone. Health risks will be greatly reduced at the application site since the City of Greeley will maintain control of the effluent during reuse and dis- charge. Some risks would be associated with the farming personnel during operations, but education and special precautions should minimize these risks. Odor . The potential for the development of odors increases with the amount of time the wastewater is retained in the transmission line from the "Delta" to the lagoons. Air scrubbing of odors, prior to discharge, and a submerged inlet at the lagoon will help to minimize the release of odors•to the atmo- sphere. Decaying material which has settled to the bottom of the reservoir is capable of producing odors when the material is exposed during low reservoir levels. Proper aeration of the lagoons will reduce the occurrence of odors from the reservoir during low levels. Potential odors at the land application site will be minimized by thorough aeration of the soil . Proper farming techniques including plowing, discing, and cultivating should provide odor free conditions in the soil . - 11 - Visual The proposed reserovir and lagoons will alter the topographic features of IIthe immediate area. The greatest impact will occur during construction when exposed soil will contrast with surrounding vegetation. However, as vegetation IIestablishes on the slopes of the facility, this impact will be significantly reduced. Analysis of the visual features of the area indicates that the llrolling terrain of the area will aid in further reducing the visual effects • beyond the immediate site.II The 4 day lagoons can probably be located away from county roads thus IIreducing the visual impact . The exact location of the lagoon will be selected during the final design stage of the project. The conversion of dry land to llirrigated lands should not produce any visual impacts since the surrounding area is also agricultural . Agriculture The land application system will convert between 2,000 and 3,000 acres of historically dry land to irrigated land. This is in keeping with EPA's agricultural land policy of preserving agricultural land. At this time, the crops that would be cultivated have not been determined. Corn and alfalfa are the most probable crops that would be grown. Both crops have high annual water requirements and their nutrient uptakes should remove most of the wastewater nutrients. In addition, there is a local market for these crops due to feedlot operations in the area. A third crop option would be reed canarygrass. Reed canarygrass has been irrigated with applications of water of two inches per week (in/wk) which is comparable to corn (2.5 in/wk) but has the benefit of a longer irrigation period. Reed canarygrass can be irrigated as long as the soil will take water. It is also a nutrient demanding crop. Local markets have not been identified at this time which may be a major drawback to this crop. - 12 - The buildup of toxic or hazardous materials in soil , crops or livestock has a minimal potential for occurring. Concentrations of these parameters in 1 domestic wastewater have not proven detrimental in similar land application I projects. The implementation and enforcement of pre-treatment requirements on industries along with detention/storage of the wastewater prior to application will minimize toxic materials buildup at the application site. It will be necessary to occasionally monitor the pH of the reservoir water to insure a more basic condition. This basic condition will reduce the tendency toward solubility of metals which occurs with more acidic conditions. No impacts to livestock as a result of being fed silage or grain produced under this system are expected . LAND USE The land application system will have significant land use impacts. 1 Between 2,000 and 3,000 acres would change from rangeland to cropland . Irrigation in the study area from the land application alternative will have a positive effect on land use. This area is not looked on as an area of commercial or residential development. Production value of the land in the study area would increase as well as the generation of crop revenue. There would be little detrimental long term land use impacts on adjacent farmland. WATER SUPPLY The location of the storage reservoir and lagoon system is near existing North Weld County Water District distribution lines. NWCWD has agreed to provide service to the site for domestic use. A copy of the letter from NWCWD indicating the ability to provide water service is included in this document. The NWCWD must satisfy the requirements of the Northern Colorado Water Conservancy District in providing service to any customer. The reservoir and lagoon site at Site I does not meet one particular requirement which states - 13 - BOARD OF DIRECTORS �.., [_RNEST TIGGES NORTH WELD COUNTY WATER DISTRICT �- ALEX HEIDENREICH - ROBERr. ALKIRE -' HIGHWAY 85 LUCERNE. COLORADO 80646 GARY SIMPSONf� LYLE NELSON. MGR _TOM REED � P O. BOX 56 • PHONE 356-3020 `'` ' 1 "r19�0 September 15 , 1980 `'`-'' RE: Water Service .TTN: DICK urJT,;A Dear Sirs , This letter is in response to your inquiry regarding water ' service to the following described property : . The city of Greeley ' s wastewater disposal site south of Barnesville , Colorado , in port-ion of 6 N R,63 W. Providing service is to land that is in boundry of Northern Colorado Water Conservancy District , or land that is agreed by Northern Colorado Water Conservancy can be served by North Weld County Water District . 1 . Water service is presently being provided to the above described property . 2. X Water service can b- mdde availal) i e to the above described property provided all requirements of • the District are satisfied. If contracts have not been consuttrated with North Weld County Water histri- , t within one year from date of this letter . this letter shall become- nun and void. Additional comments . • Sincerely , NORTH WELD COUNTY WATER DISTRICT • • - J I y D. Nelson , Manager I,DN/rM r that the site at which the water is used must fall within the boundary of the Conservancy District. The Conservancy District boundary runs •through the center of the reservor and lagoon site, and the water will be used at buildings located just outside the boundary. This problem will be resolved through Greeley's participation in the Windy Gap Project. ACCESS ROADS • • Two access roads to the treatment site are proposed. These two roads will be laid out to provide access around the entire reservoir and lagoon site. In this way, the roads can be used to operate and maintain the facili- ties in addition to providing access to the site. The southern access will enter the treatment site at the intersection of County Roads 62 and 61 and cross the storage reservoir dam. This access will terminate near the control , lab, and maintenance buildings . The north access will enter the treatment site at County Roads 64 and 61. This road will follow the northern and eastern edges of the reservoir and also terminate at the control , lab and maintenance buildings. Other roads within the site will be located on the reservoir and lagoon dikes, and field roads within the land application areas will develop between center pivots. Any heavy traffic will enter the site from the northern access to avoid crossing over the reservoir dikes and dam. The City of Greeley will be responsible for maintenance and improvement of all roads within the site. However, part of the northern access is currently a dedicated county road even though it appears to be nothing more than a field road. The entity responsible for maintenance of this portion of road has not been determined at this time pending a decision on this special use permit application. - 14 - • Traffic at the site will be minimal . The most significant volume of traffic will be the result of employees arriving for work and •later departing. Vehicles will be moving around the site daily as employees operate and maintain the facility. Truck traffic to the site will be infrequent. Large delivery truck will occasionally bring supplies to the maintenance building. Trucks may- also be required during sludge removal from the lagoons, but this is expected only once every two years. PROPERTY OWNERSHIP The City of Greeley does not currently own the lands which are within the special use boundary. The proposed site is owned by several individuals who carry on agricultural and livestock operations on the land. The introductory letter from the City of Greeley's Attorney indicates the reasons for delaying in the purchase of the treatment site. • - 15 - NAMES OF OWNERS OF PROPER-1' WITHIN 500 FEET . -/ , Please print or type . NAME MAILING ADDRESS Jackson B. Wells . A. Bruce & Jackson B. Wells Gill , Colorado 8062.4 1313 Sherman Ste. 620 State Board of Land Commissioners Denver, Colorado 80203 . Rt. 1 Box 15'Z S.L.W. Ranch ' Greeley,Colorado 80631 Vera Peterson Rt. 1 Box 39 Kersey, Colorado 80644 William & Dorothy Walker 34380 Weld Co, Rd. 67 Rt. 1 Box 51A Gill , Colorado 80624 72 Broad Street —" Elizabeth Armstrong c/o Mrs. Hugh Dunn Guilford, Conn. 06437 ,, fit. I Box 43 -' C. Millard Bashor Gill , Colorado 80624 NE of Gill Duane G. Bashor Gill , Colorado 80624 Jackson B. Wells A. Bruce Wells c/o Jackson B. Wells Gill , Colorado 80624 I . N.U. Box z143 Ethyl Margaret Nesbitt Bullhead City, Arizona 86430 • Rt. 1 Julia M. Cook Gill , Colorado 80621 Rt.Altena & Julia M. Cook I Gill , Colorado 806'24 Carroll& Arlene Bishop 32138 Weld Co. Rd. 68 Gill , Colorado 80624 602 S. 2nd Street Frank J. & Maria B. Granado • Kersey, Colorado 80644 2224 S. Ogden Street Theodore L. Nieman _ Denver, Colorado 80210 ' Jackson B. & 'Lillian M. Wells Gill , Colorado 80624 Box 836 Fairmeadows Land Co. Greeley, Colorado 80632 Rt. I Box 21 Lee A. & Norma J. Miller Gill , Colorado 80624 Rt. 1 Box 24 Jacob. Jr. & Shirley L. Miller Gill , Colorado 80624 Rt. 1 Box 43 David E. Bates c/o C. Millard Bashor Gill , Colorado 80631 i , r PART II BEDROCK GEOLOGY INVESTIGATION • • • • GREELEY 201 WASTEWATER STUDY BEDROCK GEOLOGY INVESTIGATION for ARIX Engineers P.O. Box 2021 Greeley, Colorado 80631 and City of Greeley Civic Center Complex Greeley, Colorado 80631 by ESA Geotechnical Consultants 317 Walnut Street Fort Collins, Colorado 80524 • August 1980 ESA Geotechnical Consultants ESA Geotechnical Consultants DOUGLAS H HAMILTON 317 Walnut Street, Fort Collins, Colorado 80524 RICHARD L MEEHAN EUGENE A NELSON (303) 221-2612 RICHARD C HARDING GEOLOGY KARL YONDER LINDEN GEOPHYSICS LEONARDO ALVAREZ • SEISMOLOGY MICHAEL T DUKES ENGINEERING PATRICK 0 SHIRES _ GEOHYDROLOGY ROBERT H WRIGHT VICTOR F VIETS PHILIP A FRAME W ROGER HAIL JULIO E VALERA BARBARA I. DWIGHT HUNT TURNER August 14, 1980 C RES 8 SCOTT ICHARD WILLINGHAM 2189 r SALLY W BILODEAU TIMOTHY J MANZAGOL • •Mr. Gary R. Windolph, Vice-President ARIX P.O. Box 2021 Greeley, Colorado 80631 Re: Geologic Investigation, Greeley 201 Wastewater Study Dear Gary: We are pleased to transmit the above referenced report on bedrock condi- tions at the proposed land application site east of Greeley, near Barnesville. We have provided a bound copy for your files as well as an unbound copy for reproduction. To ensure good copies of the drawings, we are transmitting the original mylars. We would, however, like to have them back after printing is completed. We at ESA are pleased to have had this opportunity to work with ARIX, the City of Greeley, and other consultants on the team. We have enjoyed both the technical aspects of the work and the association with other individuals working on the project. We look forward to future projects with ARIX. Sincerely, ESA GEOTECHNICAL CONSULTANTS e7-'''e---1/4—/Li' W. Roger Hail, Principal Gil a / 7/..e., _ Barbara L. Turner, Project Manager BLT:nb Palo Alto, California Oak Harbor,Washington Fort Collins,Colorado Table of Contents Page I. INTRODUCTION AND SUMMARY . A. Background I-1 B. Purpose I-1 C. Scope I-2 D. Authorization and Performance I-2 E. Summary of Conclusions I-2 II. SITE GEOLOGY A. Regional Setting II-1 B. Geology of the Site II-3 III. SITE HYDROGEOLOGY (BEDROCK) A. Hydraulic Characteristics III-1 B. Permeability Distribution III-3 C. Existing Water Levels III-4 IV. SEEPAGE ANALYSIS (BEDROCK) A. Land Application Area IV-1 B. Storage Reservoir IV-4 V. BIBLIOGRAPHY V-1 FIGURES 1. Location of Exploratory Borings 2. Location of Oil and Gas Wells and Regional Geologic Sections 3, Geologic Map 4. Water Levels in Laramie Formation and Fox Hills Sandstone, July 1980 S. Location of Seepage Zones ESA Geotechnical Consultants TABLES A. Summary of Field Permeability Testing B. Summary of Seepage Estimates Plate Numbers 1-5 and Supplements A, B, and C were not included in this report. ii ESA Geotechnical Consultants ' , r I. INTRODUCTION AND SUMMARY A. Background For the past several years, the City of Greeley has been working on a plan for wastewater treatment and disposal. After consideration of a num- ber of different alternatives, land application was selected as the preferred method, and a site was tentatively chosen principally on the basis of cost ' and water rights considerations. Because little bedrock information was available, members of the City Council and the Citizens Advisory Committee expressed concern about the possibility of important water losses through the bedrock. The primary reasons for their concern were: 1) that farming operations in the Crow Creek alluvium northwest of the site could be affected should the project cause ground water levels to rise; and 2) exces- sive water losses to the southeast would diminish the water available for augmentation, should it be necessary. The City requested and obtained a grant from EPA to study the bedrock formations beneath the site, and to evaluate the potential for seepage losses through the bedrock. After interviewing several consultants, the City selected ESA Geotechnical Consultants to perform this work. B. Purpose The purpose of ESA's work was to study the subsurface bedrock geology at Site 1, to determine the hydraulic properties of the rocks underlying the site, and to evaluate the effect of bedrock conditions on the feasibil- ity and operation of the proposed land application project. The present study has been conducted to determine whether seepage amounts could be significant and whether fracture zones are present in the bedrock that would concentrate seepage toward a part of Crow Creek Valley, or to the southeast where recovery could be difficult. I-1 ESA Geotechnical Consultants C. Scope The scope of ESA's work included a review of published data, field studies at and near the site, data analysis and report preparation. Also, included were attendance at weekly project meetings and presentation of results to the City Council, Water Board and Citizens Advisory Committee. All of ESA's studies were limited to the bedrock formations. The unconsolidated overburden, which plays a crucial role in the feasibility and ultimate performance of the project, was investigated by ARIX Engineers of Greeley and Resource Consultants, Inc. of Ft. Collins. Some of their results have been used in developing the conclusions presented here, but no attempt was made to verify or reproduce these data during field investigations. D. Authorization and Performance ESA's work was performed as a subcontract to ARIX Engineers in accord- ance with our proposal submitted on May 14, 1980. Authorization to proceed was given by telephone on June 11, 1980 and verified by a letter from ARIX dated June 16, 1980. ESA's Principal Hydrogeologist Roger Hail was responsible for general supervision and review of the work, and performed some of the seepage analyses. Barbara Turner, Senior Hydrogeologist, acted as Project Manager and Principal Investigator. Supporting staff included Sally Bilodeau, Alan Isreal, Debbie Lienhart and Nancy Bartlett. E. Summary of Conclusions 1. The regional geologic studies indicate that Site 1 is as good or better than other potential sites in the project area. Site specific studies (test drilling) of bedrock conditions were not made at other sites. However, regional subsurface data from published sources and oil and gas test wells indicate relatively uniform geologic conditions throughout the project area, 1-2 ESA Geotechnical Consultants resulting in little or no significant geologic advantage of one site over another with respect to bedrock conditions. 2. Examinations of core samples collected during drilling indicated that nearly all of the fractures are essentially bedding plane partings and are sub horizontal (0-S0) . No fracture zones were observed that would provide rapid seepage paths downward through confining shale layers or that would provide preferred horizontal flow paths which could concentrate ground water . flow in any particular area. 3. Very conservative bedrock seepage analyses were performed for the spray irrigation area. A range of seepage estimates was developed, using both high and low permeability values from field test results. These analyses show that annual seepage losses through the bedrock at the site are estimated to be less than 1 to 4 percent of the total applied water, an amount which is insignificant in an overall water balance. Because of the conservative nature of the analyses, actual seepage rates will probably be at or below the lower part of the estimated range. 4. Seepage analyses indicate that a maximum of only 200 acre-feet per year could be transmitted through the bedrock toward agricultural areas in the vicinity of Crow Creek. Actual seepage amounts would probably be much less and the water would be dispersed over a large area that is at least five miles long. Even if the maximum estimated amounts of seepage were lost from the land application area by bedrock seepage, it should not be large enough to substantially affect water levels in the agricultural areas to the west. These seepage losses, however small, can be recovered within the Crow Creek watershed and are not necessarily lost to the project or to landowners in the area. 1-3 ESA Geotechnical Consultants rr r 5. There will be bedrock seepage losses in a northeasterly ar.1 south- easterly direction that will amount to a maximum of 360 acre-feet per year. Again, the actual amount will probably be much less. Although, this amount of seepage is insignificant, most of it will be effectively lost from the Crow Creek watershed. 6. Very approximate analyses of seepage from the storage reservoir suggest that annual seepage losses through the bedrock beneath the reservoir would amount to less than 5 percent of storage capacity, assuming full storage all year round. Since full storage will not be used most of the year, annual bedrock seepage will probably be less than 2 or 3 percent of storage. Seepage conditions in the overlying alluvial deposits are much more critical to dam design and reservoir seepage control because these materials are much more permeable. These conditions should be defined and analysed in detail to support design of the dam and reservoir. 1-4 ESA Geotechnical Consultants • r. -7 ' r 10 r. �. , • I M t /I G 1 13 i 1:..., A. t M a 1 " / �i r7. ! —O a"i 1\ 21 ,I 22 `/'' 23/,r ?r (//�` j 24 • /^ \ y ! `�i \Y' Cl / �'.-r-fib '/� \ C, ,• M rt(11, -_ \ J EXPLANATION ' '� s Air Rotary Boring, �� , ESA 198O. 1 ARD-I X28 :/ -r' - `--''- _ - ' C-1 �, 1 •,4a - •\,`.,....,,, ,,, � '' 26- 28 • Core Hole, ESA iP8O. , •. - : } r.';Ali r Gill 1 1 I:- _r_ - -.°' Note: All exploratory borings were 33 _ : 3 35 % ' completed as observation •.cells i`"�T s, 36 i ' ` with 2 in. dia. casing k core i (Tut.Lake( , . an holes and 4 or 5 in. dia. I,, _ - / _ ".4-) casing in air rotary holes. w �r SCALE k r , , ' 0 5000 4', 1 -a� -2- ,r=' ; '1 feet _,/ J ) �, `� ESA Geotechnical Consultants '- / fort coihos co,orado G ,\ )!‘43\-1-,_,- t �b\- Greeley 201 Wastewater Study \\ `�.�-.,,-.ter'—\ia� ,• —`" 1e LOCATION OF EXPLORATORY BORINGS M ..- -' _ t ChecKeo ov5Jdt✓oW.c.z--e-�u-�Date tf/3, 80 Projee `o I Figure Nu 400roved by VI/-- 'f, t Date 8,/7,T, P ' Q 21 R9 '1 A ' T - ty I • ., 4 :b 1, �, :n' ;sI ' `� l lb h ;S Oo I 14 tom'_ �� J i \'^; II N. I . .' _ "'%, -)4." f 'frjH ' ' I \ . 'Y' r -- l s, 91, i ti r A. _`rtef1I 61 r �E 1N,I, 4 } i, _vv C . G \\_i Z�,.,». a -- -- ] —9♦ y Fad Terra \ I " / . \HI ri y `, •,4•. J S 044 I Torn vessels. S^f. * ` Lo.,., Nr4'; yAlex Fielde�trl chN0.1 w ° c,"c,a.,,.t ° ° S ...ice—. ,_I s=___ — ,4_i..,:fi— �,_4 '- r :‘ y.`0''',"-',•• — { , iy - , I 1, ) I z a f :7,--- — -- '0s,o-_--,a� __c - .. '=•-�� ,I of` - i •. S D Uohnson - "6, Gill '-*/ ZO2L� r PI€t.�k ceder• — I - 1 — J r= '' , ' B 4 i; . �_ _ ,. . _ _• .— -- I Choncllelet el, — N , — „ - I -Stat ' V`Vo 4 r�,,,,,,Ar1 4 ,. �L� �=5 `A' -�— a _!I•:• 1 r 4I \• O fi 1 Q0� ' sl .. ,. � - , , -- — "e oa.`tl _.. The 't\ \ sa '''2 i, ' 8 o ,- . SCALE .z. I ` fi _ a+ a ,I. - 0 I0t000 1 I , ,,,,,,N° I' feet a Iu A".; ESA Geotechnical Consultants t_ caK a5x c�ev` \ Fort Collins Colorado y n1C S .4 Iit .° °•fax ' Greeley 201 ',,lastewater Study _I -" - .Pa Arne-dean Pef oleim 4r(1,-?...,- AND RF OF OIL GAS GIAr FoLnGIrSF CEInSS ' (i— UPRFI-Nv 'f' `i i F SiPro ect `o F ure �o Ctiecked byrf-, - Date 3 Approved by * `•2e. DdIP '1 /� 'CI ., II. SITE GEOLOGY A. Regional Setting The proposed land application project is located about ten miles east of Greeley, in the low hills southeast of Crow Creek. Most of the study area is situated on land owned or leased by Jack Wells , and is mainly used for grazing. It is essentially rolling prairie land with sparse vegetative cover. Topographic relief is fairly low with the maximum variation being several hundred feet. The proposed land application site comprises approximately seven square miles on the northeast side of a low ridge. Elevations of the site range from about 4,650 feet to 4,800 feet above mean sea level near the ridge crest. A storage reservoir will be located at the west edge of the project area, in sections 31 (T6N R63W) and 6 (T5N R63W) (See Figure 1) . The site area is situated on the north-western rim of the Denver Basin along a doubly plunging syncline. Typically the rocks are nearly flat- lying, dipping gently westward at one to five (1-50) degrees . There are minor flexures and folds regionally, but these are conspicuously absent in the study area. This absence is important from a hydrogeologic point of view, lessening the likelihood that compressive forces would have caused frac- turing and faulting in the sedimentary rocks underlying the site. A series of regional cross sections were constructed across the site area, using electric logs from oil and gas test holes. The test holes and cross section locations are shown in Figure 2. These cross sections, Plates 1 through 5, demonstrate clearly the absence of major structural features in the site region. The sections were prepared using the total length of the oil and gas logs (to depths of 6,000 to 7,000 feet) , but only the II-1 ESA Geotechnical Consultants 7r uppermost 3,000 feet are shown, as units in the lower part of the geologic section show the same relationship as those above. Due to the generally subdued topography and lack of well defined stream cuts , rock outcrops in the site area are not abundant. However, from the regional sections and from published geologic maps, it was determined that rocks underlying the area belong mainly to the Laramie Formation, of Upper Cretaceous age (about 100 million years old) . According to Romero (1976, p. 19) : "The Laramie Formation is considered by most investi- gators to consist of two parts, a lower part composed pre- dominantly of sandstone and an upper part composed largely of shale. The lower 30 to 80 meters (100 to 260 feet) of the Laramie consists of a series of thin-bedded, white to yellowish-orange and tan, quartzose sandstone interbedded with seams of lignitic shale and coal, and two generally prominent beds of yellowish-brown to tan and light-gray, medium-grained, quartzose sandstones. The two sandstone beds form the base of the Laramie and from the base upward are termed the A and B sandstones. An intervening thick- ness of about 2 to 6 meters (about 5 to 20 feet) of shale commonly separates the two sandstones." Most of the Laramie Formation has been eroded away from the site area, with less than a few hundred feet remaining. The Laramie Formation is underlain by another Upper Cretaceous unit, the Fox Hills Sandstone. The Fox Hills consists of up to 400 feet (Wacinski, 1979) of sandstone and sandy shale. The lower part is pre- dominantly shaley sandstone and sandy shale while the uppermost part (Milliken Member) consists of a massive sandstone unit, characterized by hard calcareous concretionsup to several feet in diameter and small round iron concretions. The upper Fox Hills, together with the lower Laramie A and B sands, make up what is commonly referred to as the L-F aquifer. In the Denver area, where it is fully saturated, this aquifer supplies quan- tities of water adequate for stock and domestic wells, but well yields are generally insufficient for irrigation uses. 11-2 ESA Geotechnical Consultants f Beneath the Fox Hills Sandstone is a very thick (5,000 to 7,000 feet) marine unit, the Pierre Shale of Upper Cretaceous age. The uppermost 2,000 feet of the Pierre is transitional to the overlying Fox Hills Sandstone, and consists of interbedded shaley sandstones and sandy shales (See electric logs on regional cross-sections) . The lower part is a massive clay shale sequence. The Pierre is nowhere exposed in the site area, but underlies it at a depth of about 150 to 500 feet. Overlying the bedrock is a thin veneer of Quaternary age, uncon- solidated dune sand and fluvial sand and gravel deposits ranging in thick- ness from a foot or two to more than 80 feet in the buried ancestral channel of Crow Creek. These units are unsaturated over much of the site, but in • the Crow Creek Valley and along the northwest edge of the site, they are an important source of water for irrigation. From samples recovered during drilling, the dune sand was observed to be sub-rounded, fine-grained to medium-grained, fairly uniform, and uncemented. B. Geology of the Site As part of ESA's investigation, 13 boreholes were drilled on and around Site 1. Details of the field exploration program are given in Supplement A and field data are contained in Supplement B. The results of this and previous work done by others show that in most of the proposed land application area, the bedrock is covered by unconsolidated deposits , a few feet to more than 85 feet thick (See Figure 3, Geologic Map) . ESA's work was not specifically concerned with the alluvial units overlying the study area, as the firm was commissioned to evaluate seepage potential through the bedrock. However, unconsolidated materials were carefully described in the logs of all boreholes drilled for this investigation. The units encountered can be classified as alluvial deposits, terrace deposits 11-3 ESA Geotechnical Consultants l -1 N 1 EXPLANATION \ , I Geologic Units Qd Dune Sand, Quaternary age. Symbol of underlying bedrock unit in parentheses. to (;y „4 _-,„1 ;') l Ovf Valley Fill, Quaternary age Consists I . of unconsolidated sand, gravel, . _-,:f7,„. _, , ,_: 1 1, .�!.-.�;_>- ,_x r,_��. a r _ , silt and clay; locally more than 85 . feet thick. Symbol of inferred r- i ("1, KI \\ I underlying bedrock in parentheses " �- :S 54 1 K/ Laramie Formation, Upper Cretaceous ( age. Consists of interbedded shale, A ..,/ , siltstone, claystone, and sandstone with some thin coal beds x r ` - - j,14—, Mostly sandstone in lowermost r - l 50 to 100 feet. .' •i 22 ®. 23 <`,/ Y�;",. 2, Kf Fox Hills Sandstone,Upper Cretaceous o 6 f b age. Consists of sandstone with �' " .\` ( interbedded sandy shales. -;�, .+. ) ='1 `' liJ -/ Symbols j I RD 19 Air rotary boring, ESA 1980. , . \\ ,kAr6-I,-- , ' 2 ,�`; '( z6 ' •i5 c-I • Core hole, ESA 1980 - - _ 1 ? •.. a _ _ • •�; ,L.Gill } X \ ••• Geologic contact, approximately ' \ I rt'._ RD-2 • located. •. Buried contact between Fox Hills •?• Sandstone (Kf) and Laramie ''34,- K a 1� 36 • Formation (K/ ), approximately 1\'. located. Queried where inferred - i t / I Approximate location of buried contact ��• _ _• - -...Y.-._ •_ _ _ _ _yti; _ �_ — between top of L-F aquifer zone \�/�� /l�, and overlying rocks Stippled on ka\� / r r L-F side of contact. �, _ -4 _\� Sources: Hershey and Schneider,1972, rK J , Schwochow, Schroba and Wicklem, 1974, and 3t , \ r _,4' Weist, 1965 - _" \\� r's� . "J ESA Geotechnical Consultants I r`F• \ rorr Collins Colorado { . r, \ J-" ` Greeley 201 Wastewater Study io• I_ :iN ,' :2 GEOLOGIC MAP Checked bv<- '�� Date'. 9r ProleR No Figure `o T� 1 _ �.- F i3 8-I 21 P,g 3 �ooroved by � �� Dater t or dune sand. They typically consist of silty sand, clayey sand, sandy clay, gravelly sand, or sand. The sand is generally sub-rounded, fine- grained, poorly graded, and uncemented. Bits of organic matter, coal and shell fragments are commonly found in small amounts in the overburden. Beneath the unconsolidated material, bedrock is principally the Laramie Formation, of Upper Cretaceous age (about 100 million years) . The maximum thickness of Laramie rocks penetrated by ESA's drilling was 155 . feet in Boring C-4. In this borehole, both the A and B sands in the lower Laramie were penetrated. They were found to be very dense, but largely uncemented. In this and other boreholes the typical sandstones were fairly uniform, fine to medium grained, sub-rounded, and uncemented to weakly cemented. They range in color from light brown to bluish gray and contain thin interbeds of coal, clay or siltstone. There are occasional zones of calcareous and ferruginous concretions. Sandstone beds typically exhibit moderate weathering (iron oxide staining) , and low to moderate hardness. Bedding is typically massive, but subhorizontal bedding (0-5°) can be seen where interbeds of claystone are present. The sandstone is saturated where it is present immediately beneath the alluvium of Crow Creek and at lower elevations on the proposed irrigation site, but is unsaturated along the southeast boundary of the land application area, near the ridge crest. The claystone and siltstone units range from light olive gray to moderate yellow brown and are variegated in many cases. Some of the clay- stone shows platey cleavage and grades downward to a more fissile shale. Thin lignitic beds were encountered in most of the Laramie section drilled at the site, but coal beds were found only in RD-7 and C-4. The maximum thickness of coal was five feet in RD-7. In the five core holes drilled, the claystone and siltstone units exhibit the spectrum of fracturing ranging from closely fractured near the surface to little to no fracturing 11-4 ESA Geotechnical Consultants at depth. In three of the five holes, fracturing and weathering decreased to little or none at 20 to 30 feet below the bedrock surface. As an example, in borehole C-2 sandstone bedrock was encountered at 24.0 feet and clay- stone was encountered at 34.0 feet. From 34.0 feet to 36.0 feet the clay- stone was closely fractured and then became little fractured, remaining in this state to the bottom of the hole at 74.2 feet. In borehole C-4, however, the claystone, siltstone, and sandstone core was closely fractured to 76.7 feet. Bedding plane partings may be a more appropriate term for the fractures found in this rock, as they are aligned along the bedding planes at 0-Se. There were few to no steeply dipping fractures seen in the cores, which would preclude the downward movement of irrigation water through the claystone along fractures. It was also difficult to differentiate natural • fractures from mechanical breakage of the core due to drilling, when there is no iron oxide staining or other sign of weathering along the joints. In summary, no intense fracture zones were encountered that would provide rapid seepage paths downward through confining shale layers or that would provide preferred horizontal seepage paths which could concentrate ground water in any particular area. Stratigraphically below the Laramie Formation is the Fox Hills Sand- stone, also of Upper Cretaceous age. This formation is relatively thin, and attains an average estimated thickness of 135 feet in the project area. The upper part of the Fox Hills consists principally of sandstone, while the lower part contains a greater proportion of sandy shale. interbeds. It is somewhat difficult to differentiate between the lower Laramie Formation and the Fox Hills Sandstone or to assign a contact to them. In the field, they were differentiated primarily on the basis of stratigraphic position and rock types. Also, the Laramie Formation contains coal while the Fox Hills Sandstone, being marine, lacks coal and contains some obvious marine fossils. As noted above, the lower Laramie sandstones and the upper 11-5 ESA Geotechnical Consultants Fox Hills sandstone, where they are saturated have historically been treat- ed as a single hydraulic unit, known as the L-F aquifer. Exploratory borings drilled for this investigation did not penetrate the full thickness of the Fox Hills Sandstone. Where Fox Hills rocks were encountered, they consisted mainly of very hard cemented sandstone (RD-2 and RD-3) with some claystone and siltstone (as in the bottom of C-4) . The sandstone encountered in drilling was fine to medium grained, sub-rounded, poorly graded and well cemented. It was so hard that drilling had to be discontinued. It ranged from medium dark gray, to yellowish brown in color. Horizontal bedding was observed in some of the samples (0-5°) , but for the most part, the unit is fairly massive. Claystone and siltstone beds were gray to yellowish brown, with scattered pelecypod fragments and sand and silt lenses. The Fox Hills does not outcrop in the site area, but is present immediately beneath the alluvium in the lower part of Crow Creek Valley, and probably subcrops beneath all or part of the storage reservoir site, as shown in Figure 3, Geologic Map. Stratigraphically below the Fox Hills is the Pierre Shale, which neither outcrops nor subcrops in the site region, and was not penetrated by the exploratory drillholes. From the samples recovered during coring operations , it was determin- ed that most of the claystone encountered was relatively tight and un- weathered, except for several isolated intervals scattered about the study area. It was also determined that the majority of the sandstones encounter- ed were dense, massive, sub-rounded to rounded, little weathered, non-cemented to moderately cemented, and relatively pervious. There were localized zones of concretions, but these were rare. Much of the sandstone encountered 11-6 ESA Geotechnical Consultants was uncemented, which caused caving of the borehole walls during the drilling operations. Within the Laramie Formation are thin seams of coal varying from one-inch to five feet (1"-5') in thickness. These seams did not appear to be continuous for any great distances in the study area. No regional trends concerning fracturing and weathering could be determined with the exception that the uppermost few tens of feet in the bedrock (immediately beneath the overburden) are typically more fractured along bedding planes and more weathered than the underlying units. However, the excellent core recovery which was achieved is further evidence that the rocks underlying the site are relatively unfractured, as recovery is usually poor in sheared or complexly fractured rocks. 11-7 ESA Geotechnical Consultants - r III. SITE HYDROGEOLOGY (BEDROCK) A. Hydraulic Characteristics ESA investigated the hydraulic characteristics of the bedrock units underlying the site by performing tests in the boreholes both during drilling and after installing slotted pipe. Three types of tests were performed to evaluate field permeability (hydraulic conductivity) : falling head, slug tests, and pumping-in tests. Details of these tests and analyt- ical methods are explained in Supplement A, Results of the 61 tests are presented in Table A; where more than one method was used to analyze the test, field permeabilities derived from each are given. Reliable storage coefficients could not be determined without long-term pump tests. However, published data for the L-F aquifer provides a good estimate as noted below. Claystone, siltstone and shale. The data in Table A show that the field permeability of the fine-grained rocks is very low, even in the weathered zone. The highest field permeability value recorded for the fine-grained rocks under the site is 131 ft/yr in RD-7. It should be noted that the claystone permeabilities in RD-7 decrease rapidly with depth. This is due to the combined effects of less weathering at depth, and in- creasing degree of saturation as each test is performed. As the claystone and shale are wetted, they tend to swell, closing small fractures or openings, and causing permeabilities to decrease. Under the site, most of the shale and claystone is above the saturated zone, so tests were mainly performed in unsaturated rocks. The geometric mean of all test results in the fine-grained rocks was computed from the data in Table A. Where two or more methods were used to analyze a single test, a simple arithmetic average of the resulting values from different methods was used for input III-1 ESA Geotechnical Consultants N >' a) •ri 4-1 I.-1 1,.1 N cd .0 Q I QC) t� QQQ . C) .c OO .:C Q i V UV V V L3 C3 <C QC) Co Q <4 on .O ca O •ri 4i f. '-1 O a a) a v .-i CS >. i•1 .--1 C, 01 Co Ln O .D t7 Ln o0 Q1 .--1 M O• r-i >. ri 1 .-1 M CT N N) .-1 N ri V) N N CD 0 I-1 O 01 N N CO V) C1 I ) N ,4 N .D N N •r1 . 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The field tests performed provide data on the horizontal (along bed- ding) field permeabilities of the rock, since the bedding is oriented approx- imately perpendicular to the drill holes. This is the preferred flow path within the rock mass, and permeabilities in this direction will be higher than in any other direction. As a result of interbedding and absence of vertical fracturing within the Laramie Formation, the vertical conductivity (Kv) will be much less than the horizontal conductivity (Kh) . At this site, Kv is estimated to be at most 1/10 Kh, and may be as little as 1/100 Kh. Sandstone and coal. The test results in Table A show that the field permeability of sandstones, while generally greater than the fine-grained rocks, is highly variable. Some of the lowest field permeability values resulted from tests in relatively thin sandstones , stratigraphically above the L-F "aquifer" zone. Correlation of units from borehole data showed that these sandstones were not always laterally continuous, and this may be one reason for their lower permeability. Test results in the lower Laramie and in the Fox Hills Sandstone (L-F zone) showed generally higher field permeabilities , ranging from 32 ft/yr to 3,141 ft/yr. The range of field permeabilities reported for the L-F aquifer in the Denver Basin was recently summarized by Romero (1976, p. 42) who suggested a probable range of 10-35 gallons per day per foot2 (488 to 1,708 ft/yr) . Most of the sandstone test results at the site fall into or below this range. Extremes at both ends of the scale are probably attribut- able to inherent errors in test procedures or to unusual conditions affect- ing the test, such as caving of the borehole walls. Geometric means of the 111-2 ESA Geotechnical Consultants r sandstone permeability data were calculated using two different ways : 1) the data from all tests (multiple values for a given test interval were arithmetically averaged) , and 2) only those test data obtained under sat- urated conditions. These averages are 118 ft/yr (31 tests) and 303 ft/yr (16 tests) respectively. As mentioned above, it is important to remember that test results represent only horizontal field permeabilities. Vertical field perme- abilities in the sandstone are probably on the order of 1/10 to 1/100 the , horizontal values. This affects seepage rates, since water must move verti- cally downward before it can travel horizontally within the bedrock. Storage coefficients for the L-F aquifer have been reported by Romero (1976, p. 45) to range from 0.00012 to 0.21, with an average of 0.0004 under artesian (confined) conditions and 0.15 for water table conditions. Although it is theoretically possible to determine storage coefficients from slug test data using the method of Cooper et al (1967) it is not a very reliable method because small changes in the match points selected result in large changes in storativity. The lack of site specific data on storativity is not of great importance however, since the method used for seepage analysis assumes steady state conditions. B. Permeability Distribution The interpretation of regional geologic data has been combined with drilling at the site to determine what rock types underlie the alluvium which covers the area. As described above, bedrock beneath the site consists of shale, claystone, siltstone and sandstone of the Laramie Formation and Fox Hills Sandstone. Water tests performed for this investigation show that the most permeable bedrock units are the sandstones in the upper part of the L-F aquifer zone. Based on regional and site specific studies, the approximate subcrop of the L-F zone beneath the site was delineated, 111-3 ESA Geotechnical Consultants and is shown on the geologic map, Figure 3. As this figure illustrates, bedrock subcropping beneath the storage reservoir and southwestern part of the land application area, is mainly sandstone, and in the northeast part of the land application area, is mainly shale, claystone and siltstone. This means that seepage rates through the bedrock will be less in the northeastern part of the project area. Water seeping downward will have to pass through the low permeability shales and claystones before reaching ' laterally continuous sandstone beds. C. Existing Water Levels In order to evaluate the seepage potential, it was necessary to determine the direction and slope of existing hydraulic gradients in the project area. To do this, boreholes were completed as monitoring wells (piezometers) within the bedrock, and measurements of static water levels were made after testing was finished. As would be expected, water levels reached equilibrium most rapidly in boreholes where the higher permeability tests were recorded. In two borings, RD-6 and RD-7, water levels dropped so slowly that it was not apparent until after drilling and testing were completed, that the saturated zone had not been reached. To supplement water level data from the 13 ESA boreholes, measure- ments were also made in one abandoned well and, ten stock wells with wind- mills on and around the site. Water levels measured in stock wells must be used with some caution, since, if they have been pumping, measured levels could be somewhat lower than static levels. In most cases measurements were made on days when there was not very much wind, so that data are probably reliable to within a few feet. Also, reference point elevations were not sur- veyed and elevations were estimated from topographic maps (10 foot contour intervals) . 111-4 ESA Geotechnical Consultants - r Figure 4 is a contour map of the potentiometric surface within the Laramie and Fox Hills bedrock, prepared from water level measurements taken in July 1980. Two windmill measurements are not shown; one was in section 14 5N 63W and is off the map area, but was used in drawing the con- tours. The other was in section 11, 6N 63W and is completed in a deep formation below the L-F zone. Figure 4 shows that the regional hydraulic gradient is to the southwest, but that a ground water "nose" has developed in the low hills southeast of Crow Creek. This feature is probably the result of direct recharge into the bedrock from the saturated alluvium of Crow Creek, especially in the irrigated areas around Barnesville. Drilling and testing of the bedrock formations indicate that where the L-F sandstones are saturated, they are generally unconfined, so water levels in the bedrock are generally about the same as these in the over- lying alluvium, where both are saturated. During operation of the project, a ground water mound will probably develop beneath the irrigated area, changing hydraulic gradients in and around the site. Thedimensions of this mound will depend on the operation of the project, especially the location, and amount of water applied as well as hydraulic parameters and climatic factors. Water level changes in monitoring wells will help to determine the lateral extent and configuration of any ground water mound which develops. 111-5 ESA Geotechnical Consultants I^ EXPLANATION Data points measured in July 1980: • Observation well installed by ESA, 1980. ■ Existing well / — — Approximate contour on potentiometric ' surface in Laramie Formation and Fox Hills Sandstone. Contour interval 10 feet. / SCALE 0 5000 1 r , feet ESA Geotechnical Consultants Fort Collins Co oraao Greeley 201 4astewater Study WATER LEVELS IN LARAWIE FOR",:—'0N NP fl" ILLS S PcTn^,E , . 19'0 4'Checked bv Date Jr 3 Pr Project 'No Figure Approved by •r . ? 4 IV. SEEPAGE ANALYSES (BEDROCK) A. Land Application Area Very conservative seepage analyses were made, based on field test data, to determine the maximum seepage losses that could reasonably occur through the bedrock units resulting from irrigation. It was assumed that vertical percolation would not be hindered by the anisotrophy of the sand- stone, nor retarded by shale or siltstone layers. This is extremely conservative because the vertical permeability of sandstones is normally less than 0.1 of the horizontal permeability, and the shales and siltstones have very low horizontal and vertical permeabilities. Another conservative assumption made was that water percolating downward from the irrigated areas would immediately saturate the presently dry rocks between the water table and the surface. Actually this would take considerable time, and saturation to the surface would not be permitted because a zone of aeration would have to be maintained for the growing crops. Development of a seepage mound in the bedrock units will induce flow of seepage water away from the land application area to the northwest, south- west and southeast by developing slopes in those directions. This seepage mound would dissipate slowly during the winter season and rebuild during each irrigation season. For purposes of seepage analyses it was assumed that the water table rises to the surface, sloping westward toward Crow Creek Valley. To the southeast and north, where the land surface rises, the slope of the mound was estimated as the slope between the ground surface at the edge of the irrigation area, and the present water elevation at a dis- tance of at least several thousand feet from the site. Because there are few if any open fractures, the only rock types capable of transmitting significant amounts of water are the sandstones of IV-1 ESA Geotechnical Consultants the L-F aquifer (or similar sandstones in close proximity) . Therefore, it was assumed that most of the flow in the bedrock would be transmitted lat- erally by the first sandstone layer encountered by the downward seeping irrigation water. Field permeabilities were assigned to the upper sandstones based on the range of values obtained from field tests at the site and based on published data for the L-F aquifer in the Denver Basin. Because the per- meabilities of the sandstones vary greatly, upper, intermediate and lower case values were assigned to provide a range of values for seepage amounts. The values used were 2,000 ft/yr, 1,150 ft/yr and 300 ft/yr, respectively. The high range permeability value was selected using the maximum permeability of 1,708 ft/yr reported by Romero (1976, p. 42) for the L-F aquifer, and the highest test results recorded for sandstones at the site. The low range permeability of 300 ft/yr represents the geometric mean of all the data in saturated sandstones at the site, and is probably the most reliable average permeability value for the L-F zone as a whole, beneath the site. Romero (1976, p. 42) reports aquifer test and pump test values for the L-F aquifer ranging from 0. 1 ft/yr to 1,708 ft/yr and suggests that the more probable range in the Denver Basin is 488 ft/yr to 1,708 ft/yr. A value of 300 ft/yr is slightly below the low end of Romero's estimated range, but is much higher than the lowest test data reported by him. The intermediate case was computed with a permeability value of 1,150 ft/yr, the arithmetic mean between 2,000 and 300 ft/yr. The amount of bedrock seepage resulting from irrigation was calculated using Darcy's equation, multiplying the permea- bility times the hydraulic gradient (slope of the seepage mound) times the cross-sectional area of the upper sandstone layer for the seven month irri- gation season. This is also a conservative computational method resulting IV-2 ESA Geotechnical Consultants in higher than actual amounts because the hydraulic gradient increases with time during the early part of the irrigation season, reaches a peak at the end of the season, and slowly dissipates (declines) . Therefore, the calcu- lations represent peak flows for each permeability assigned. Further, it was assumed that all 22 pivot sprinkler systems will have to be used to dis- pose of the water, which may not be the case. The computations were performed by calculating the flow through each of six zones along the site boundary, as shown in Figure 5. (Computations are provided in Supplement C) . No flow was calculated toward the storage reservoir, because the seepage mound around it will act as a barrier to flow in that direction. Gradients used for the upper and intermediate cases were calculated assuming saturation occurs all the way to the surface be- neath the irrigated area. For the lower case, saturation to within five feet of the ground surface was assumed to take place. This is more realistic, since there will have to be a zone of aeration near the surface for success- ful crop growth. Results of seepage calculations are summarized in Table B. These calculations indicate that maximum bedrock flow westward and southward (Zones 1, 2, and 6) would be approximately 200 acre-feet per year. The intermediate case and lower case estimates of flow are 112 and 28 acre-feet respectively. Most of this water would probably discharge from the bedrock units into the Crow Creek alluvium along an area at least five miles long. Part of this water will probably be intercepted by drains, but it is assumed that most of it would flow beneath the interior and perimeter drains of the land application area. However, this water would be available as ground water for use in the Crow Creek drainage. The effect of this flow on the existing water table would probably not be noticeable in the valley area because it would be widely dispersed. IV-3 ESA Geotechnical Consultants EXPLANATION Seepage zones- Incremental zone used in seepage analyses for the land application area tRD-I &RD-2, 41 f' v SCALE 0 5000 r r feet ESA Geotechnical Consultants Fort Collins Colorado Greeley 201 Wastewater Study LOCATION OF SEEPAGE ZONES Checked bvf •<+.'Mt - `"� Date P, Project No Figure NO woroved by -'Y %2 4-- Date P St' 21 ')9 TABLE B Summary of Seepage Estimates (Land Application Area) Upper Case Intermediate Case Lower Case Zone 1 154 88 22 Zone 2 34 19 5 Zone 3 62 36 9 Zone 4 45 26 6 Zone 5 256 147 37 Zone 6 8 5 1 Totals 559 321 80 Because the sandstones are flat-lying and because of seepage mounding, there will be some seepage losses to the north and southeast (Zones 3, 4, and 5) . These flows are conservatively estimated to range from 50 to 360 acre- feet per year. Therefore, the total bedrock flow away from the land appli- cation area is estimated conservatively to range from approximately 80 to 560 acre-feet per year. This is only 1 to 4 percent of the total applied water which is not significant in an overall water balance. However, because of the very conservative nature of the analyses, actual seepage rates will probably be at or below the lower part of the estimated range. B. Storage Reservoir Very conservative seepage calculations were performed to evaluate seepage potential through the bedrock underlying the storage reservoir site. (Calculations are found in the section following the text) . The method used was similar to that described above for the irrigated area. Gradients were established by taking the difference between the proposed pool elevation of 4,635 feet and the present water elevation along the north, west and southwest edges of the reservoir, and dividing by the length of the average seepage path. Seepage to the east is not expected to occur be- cause the gradient will be towards, rather than away from the east edge of the reservor. The following conservative assumptions were used in the analysis: 1. Reservoir was at full pool elevation (4,635) 12 months of the year. Actually, the reservoir level will gradually rise during the winter months and gradually fall during summer and fall when land application is occurring. 2. A 50 foot thickness of sandstone was used in computations. This is the estimated maximum which could be present. In IV-4 ESA Geotechnical Consultants addition, the sandstone .encountered in RD-3, at the southwest corner of the reservoir, was well cemented and very hard. It is likely that the horizontal field permeability of this material is low, perhaps even lower than the 300 feet per year used in the lower range of seepage estimates. 3. Anisotrophy was ignored. This is extremely conservative because the vertical permeability of the sandstones is normally • less than 0.1 of the horizontal permeability. 4. No lining of the reservoir area was assumed. The addition of lining material would increase the length of seepage paths , and therefore reduce total flows through the subsurface. The results of seepage calculations suggest that annual seepage losses through the bedrock would be less than 4 percent of storage capacity, assuming full storage (5,500 acre-feet) all year round. Since full storage will not be used most of the year, annual bedrock seepage will probably be less than 1 to 3 percent. • IV-5 ESA Geotechnical Consultants • V. BIBLIOGRAPHY American Geological Institute, compiler, 1976. Bibliography and index of Colorado geology 1875-1975. Colorado Geological Survey Bulletin 37. ARIX, 1979. Wastewater facilities planning, report no. 1, Evaluation of alternatives for Greeley, Colorado, 2 vols. Bouwer, Herman and Rice, R.C. , 1976. A slug test for determining hydraulic conductivity of unconfined aquifers with completely or partially pen- etrating wells, in Water Resources Research, vol. 12, no. 3, pp. 423-428. Briscoe, H.J. , 1972. Stratigraphy of the Fox Hills Sandstone with some comments on its suitability as an aquifer, Greeley area, Weld County, Colorado: Colorado School of Mines M.A. Thesis. Brown, R.H. , 1963. The cone of depression and the area of diversion around a discharging well in an infinite strip aquifer subject to uniform recharge, in Bentall, Ray, ed. , Shortcuts and Special Problems in Aquifer Tests: U.S.G.S. Water Supply Paper 1545-C, pp. C69-C85. Colton, R.B. , 1978. Geologic map of the Boulder-Fort Collins-Greeley area, Colorado: U.S.G.S. Miscellaneous Investigations Series Map I-855-G. Cooper, H.H. , Jr. , Bredenhoeft, J.D. and Papadopulos , I.S. , 1967. Response of a finite diameter well to an instantaneous charge of water, in Water Resources Research, vol. 3, no. 1, pp. 263-269. Edgerton, K.G. , 1973. Groundwater quality and aquifer thickness in the Eaton and Greeley area, Colorado: Rocky Mountain section, 26th annual meeting, Geological Society of America abstract, vol. 5, no.6, p. 478. Hampton, E.R. , Clark, G.A. , and Mc Nutt, M.H. , 1974. Map showing availability of hydrologic data, Boulder-Fort Collins-Greeley area, Front Range Urban Corridor, Colorado: U.S.G.S. Miscellaneous Investigations Series Map I-855-C. Hershey, L.A. , and Schneider, P.A. , Jr. , 1964. Ground water investigations in the Lower Cache La Poudre River Basin, Colorado: U.S.G.S. Water Supply Paper 1669-x. 1972. Geologic map of the Lower Cache La Poudre River Basin, North Central Colorado: U.S.G.S. Miscellaneous Geologic Investigations Map I-687. Hillier, D.E. , and Schneider, P.A. , Jr. , 1979. Depth to water table in the Boulder-Fort Collins-Greeley area, Front Range Urban Corridor, Colo- rado: U.S.G.S. Miscellaneous Investigations Series Map I-855-I. Kline, M.A. , Jr. , 1955. The structure and stratigraphy of Cretaceous rocks in Northeastern Larimer County, Colorado: Colorado School of Mines M.S. Thesis. V-1 ESA Geotechnical Consultants Major, T.J. , Kerbs, Lynda, and Penley, R.D. , compilers, 1975. Water level records for Colorado, 1971-1975 : U.S.G.S. in cooperation with the Colorado Department of Natural Resources, Colorado Water Resources Basic Data Release no. 37. Papadopulos, I.S. , Bredenhoeft, J.D. , and Cooper, H.H. , Jr. , 1973. On the analysis of slug test data, in Water Resources Research, vol. 9, no. 4, pp. 1087-1089. Schmid, W.E. , 1967. Field determination of permeability by the infiltration test, in Permeability and Capillarity of Soils, ASTM, STP 417 American Society for Testing and Materials. Schneider, P.A. , Jr. , and Hershey, L.A. , 1961. Records and logs of selected wells and test holes, and chemical analyses of ground water in the Lower Cache La Poudre River Basin, Colorado: Colorado Water Conservation Board, Colorado Ground Water Basic Data Report no. 8. 1962. Records and logs of selected wells and test holes , and chemical analyses of ground water in the South Platte River Basin in Western Adams and Southwestern Weld Counties, Colorado: Colorado Water Conservation Board, Colorado Ground Water Basic Data Report no. 9. Schwochow, S.D. , Shroba, R.R. , and Wicklein, P.C. , 1974. Atlas of sand, gravel, and quarry aggregate resources, Colorado Front Range Counties : Colorado Geological Survey, Special Publication 5-B, pp. 218. U.S. Bureau of Reclamation, 1951. Permeability tests using drill holes and wells: U.S.B.R. Geology Report no. G-97. Wacinski, Andrew, 1979. A hydrogeologic investigation of the Crow Creek Drainage Basin in North Central Weld County, Colorado: State of Colorado Division of Water Resources, Office of the State Engineer, Denver, Colorado. Open-file report August 1979. Walton, W.C. , 1978. Comprehensive analysis of water table aquifer test data: Ground Water, vol. 16, no. 5, pp. 311-317. Weist, W.J. , 1964. Hydrologic data from parts of Larimer, Logan, Morgan, Sedgwick, and Weld Counties, Colorado: Colorado Water Conservation Board, Colorado Ground Water Basic Data Report no. 16. 1965. Reconnaissance of the ground water resources in parts of F Larimer, Logan, Morgan, Sedgwick, and Weld Counties, Colorado: U.S.G.S. Water Supply Paper 1809-L. V-2 ESA Geotechnical Consultants • PART III REPORT OF A GEOTECHNICAL INVESTIGATION REPORT OF A • GEOTECHNICAL INVESTIGATION FOR RESOURCE CONSULTANTS, INC. FORT COLLINS, COLORADO PROJECT NO. 4079-80 RE: SITE I, CITY OF GREELEY SEWAGE LAND APPLICATION SYSTEM BARNESVILLE, COLORADO BY EMPIRE LABORATORIES, INC. 214 NORTH HOWES STREET FORT COLLINS, COLORADO 80521 t TABLE OF CONTENTS Table of Contents i Letter of Transmittal ii Report 1 Appendix A A-1 Test Boring Location Plan A-2 Key to Borings A-3 Log of Borings A-4 Appendix B B-1 • Grain-Size Distribution Curves B-2 Permeability Curves B-9 Summary of Test Results B-15 i • Empire Laboratories, Branch Offices P Inc.111 1242 Bramwood Place Longmont.Colorado 80501 MATERIALS AND FOUNDATION ENGINEERS P.O Box 1135 214 No. Howes Fort Collins,Colorado 80522 (303) 776-3921 P.O.Box 429 (303)484-0359 3151 Nation Way Jul 22 1980 Cheyenne,Wyoming 82001 Y P.O. Box 10076 (307) 632.9224 Resource Consultants, Inc. 105 South Meldrum Fort Collins, Colorado 80521 Gentlemen: We are pleased to submit our Report of a Geotechnical Investigation prepared for the proposed sewage application site located east of Greeley, Colorado. The attached report presents the subsurface con- ditions at the site. We appreciate this opportunity of consulting with you on this project. If you have any questions or if we can be of further assistance, please contact us. Very truly yours, EMPIRE LABORATORIES, INC. •r.-`-1 ;• V`. , •1../% s J Neil R. Sherrod �fll, ; 4'f11 R•..•:{i7,7g, ="r Senior Engineering Geologist Reviewed by: C.1 ER {{fir{C1111>tl//oft Chester C. Smith, P.E. y d President i*! 4808 0; em w. - •. -0°0 �o 7• ;qy cic 0../ '` s0 a C 74,04•'' 1. \. ' 7.Cli•: ++9p' MEMBER OF CONSULTING ENGINEERS COUNCIL rt ii REPORT OF A GEOTECHNICAL INVESTIGATION SCOPE This report presents the results of a geotechnical investigation prepared for the proposed sewage application site located approximately ten (10) miles east of Greeley, Colorado. The investigation included test borings, laboratory testing, engineering evaluation, and prepara- tion of this report. The objectives of the investigation were to (1 ) determine the soil and groundwater conditions at the site and (2) determine the physical properties of the soils encountered. SITE INVESTIGATION The field investigation, carried out on June 30 and July 1 and 2, 1980, consisted of drilling, logging, and sampling twenty-three (23) test borings. Twenty-five (25) to twenty-seven (27) borings were proposed for the site; however, there was a footage limitation of five hundred fifty '(550) feet. This limitation was reached upon completion of twenty-three (23) test borings, and for this reason Borings 5 and 22 were not drilled. The locations of the test borings are shown on the Test Boring Location Plan included in Appendix A of this report. Boring logs prepared from the field logs are shown in Appendix A. These logs show soils encountered, location of sampling, and groundwater at the time of the investigation. All borings were advanced with a four-inch diameter, continuous- type, power-flight auger drill . During the drilling operations, an engineering geologist from Empire Laboratories, Inc. was present and made a continuous visual inspection of the soils encountered. • -1- SITE LOCATION AND DESCRIPTION The proposed site consists of approximately fifteen (15) square miles of land located east and south of Barnesville, Colorado and ap- proximately ten (10) miles east of Greeley, Colorado in Weld County, Colorado. More particularly, the site is described as a tract of land situate in Sections 14, 15, 21 , 22, 23, 24, 26, 27, 28, 29, 31 , 32, and 33, Township 6 North, Range 63 West, Sections 5 and 6, Township 5 North, Range 63 West, and Sections 1 and 12, Township 5 North, Range 65 West of the Sixth P.M. , Weld County, Colorado. In general , the site consists of rolling sand hills vegetated with short and tall grasses, cactus, yucca, and sage and used for cattle grazing. The majority of the property is fenced along the section lines and county roads. Several ranch houses and outbuildings and numerous windmills are scattered across the site. Isolated trees and numerous dirt trails are located throughout the parcel . The property is bordered on the west by irrigated farmland and the flood plain of Crow Creek. In general , the site has positive drainage in a northerly and westerly direction towards Crow Creek. LABORATORY TESTS AND EXAMINATION Samples obtained from the test borings were subjected to testing and inspection in the laboratory to provide a sound basis for deter- mining the physical properties of the soils encountered. Moisture contents, dry unit weights, Atterberg limits, grain-size distribution, and permeability characteristics were determined. A summary of the test results and curves showing this data are included in Appendix B. SOIL AND GROUNDWATER CONDITIONS The soil profile at the site consists of strata of materials ar- ranged in different combinations. In order of increasing depths, they are as follows : -2- - r • (1) Blow Sand and/or Silty Sandy Topsoil : The majority of the surface of the area is overlain by a one-half (1/2) to one (1 ) • foot layer of blow sand, a material formed by wind erosion. A six (6) inch to one and one-half (1-1/2) foot layer of silty sandy topsoil underlies the blow sand throughout the majority of the site. The topsoil has been penetrated by root growth and organic matter. (2) Silty Sand: This stratum was encountered in Borings 1 through 3, 9, 11 , 13, 18, 20, and 21 below the upper blow sand and/or topsoil and extends to depths one (1 ) foot to thirteen (13) feet below present grades. A layer of clayey and/or silty sand was also encountered in Borings 15, 24, and 25 below the topsoil and/or upper sand at' depths of two (2) to eight and one-half (8-1/2) feet and extends to depths four and one-half (4-1/2) to thirteen and one-half (13-1/2) feet below the surface. This fine sand contains a large percentage of silt, is nonplastic to slightly plastic, and is generally dry to damp in situ. (3). Clayey Sand: Minor amounts of clayey sand were encountered at the site in Boring 16. This clayey sand stratum was encoun- tered below the topsoil at a depth one (1 ) foot below the surface and extends to a depth three (3) feet below the surface. A second stratum of this clayey sand was encountered at a depth of eight and one-half (8-1/2) feet and extends to a depth fourteen (14) feet below the surface. The fine sand contains minor amounts of clay, is slightly plastic, and is damp to wet in situ. (4) Sandy and/or Sandy Gravelly Silty Clay: A layer of sandy gravelly silty clay was encountered in Boring 1 at a depth three and one-half (3-1/2) feet below the surface and extends to the bedrock below. A layer of sandy silty clay was encoun- -3- tered in Boring 16 at a depth three (3) feet below the surface between the upper and lower layers of clayey sand. A five (5) foot layer of sandy silty clay was also encountered within the sand and gravel stratum in Boring 23 at a depth of forty-five (45) feet, and a four and one-half (4-1/2) foot layer of sandy silty clay separates the sand and gravel from the bedrock in Boring 24. The silty clay contains varying amounts of sand and/or gravel , is moderately plastic, and is generally damp in its in-place natural condition. (5) Sand: The sand stratum was encountered throughout the ma- jority of the site, except in Borings 1 , 13, and 21 , at depths one-half (1/2) to fourteen (14) feet below the surface. Except in Borings 23 and 24, it extends to the bedrock below or to the depths explored. In places, thin lenses of silty and/or silty clayey sand were encountered within the sand stratum, as was noted in Borings 7 and 15. In general , the sand is fine to medium grained, though it varies from fine to coarse grained. It is relatively clean, containing ten percent (10%) or less of fines, and is poorly graded in its loose to generally medium dense in situ condition. (6) Sand and/or Fine Gravel : This stratum of sand containing II minor amounts of fine gravel was encountered in Borings 23 and 24 at depths nine (9) to thirty-seven (37) feet below the surface and extends to depths thirteen and one-half (13-1/2) to greater than seventy-four and one-half (74-1/2) feet below the surface. The sand and gravel stratum encountered in Boring 23 is separated by a five (5) foot layer of sandy silty clay. In general , this coarse sand and fine gravel is poorly • graded and is moist to saturated in its medium dense con- dition. 1 -4- (7) Sandstone-Siltstone-Claystone Bedrock: The bedrock was en- countered in all but Boring 23 at depths four (4) to forty- five (45) feet below the surface. The bedrock consists of sandstones, claystones, and interbedded sandstones, clay- stones, and siltstones. The majority of the rock encountered consists of highly friable, firm to dense sandstone. The upper one-half (1/2) foot to six (6) feet of the bedrock is highly weathered; however, the underlying sandstone, claystone, and interbedded sandstones, siltstones, and claystones are firm to dense. (8) Groundwater: At the time of the investigation, free ground- water was encountered in Borings 1 , 4, 14, 15, and 23 at depths nine (9) to thirty-five and one-half (35-1/2) feet below the surface. No free groundwater was encountered in the remaining test borings to depths forty-nine (49) feet below the surface. Water levels in this area may be subject to change due to seasonal variations. DISCUSSION It is our understanding that the area under investigation is being considered for disposal of sewage effluent from the City of Greeley. The effluent is to be stored in a reservoir located in the western portion of the site and distributed by center-pivot sprinkling systems. In doing so, the dry land occupying the site will become irrigated farm land. In order to study the feasibility of this program, test borings were drilled at one (1 ) mile intervals at section corners throughout the area. A total of approximately five hundred fifty (550) linear feet was drilled. All borings except Boring 23 were drilled to the bedrock stratum. Boring 23 was drilled to a depth of seventy-four and one-half (74-1/2) feet, and no bedrock was encountered to this depth. The physi- cal properties of the soils were evaluated, both visually in the field and in the laboratory by sieve analyses, Atterberg limits, soil classifi- -5-5- • cations, and permeability characteristics. Specific yield of the soil was determined by approximate methods utilizing uniformity coefficient, effective size, and estimated porosity. In general , the soils at the site consist of silty sands underlain by clean, fine- to medium- to coarse-grained sands. Along the western edge of the area adjacent to Crow Creek, sands and fine gravels were encountered at depth. The upper silty sands contain approximately twenty-five percent (25%) to thirty-five percent (35%) fines. These soils have permeabilities of approximately thirty (30) to one hundred thirty (130) feet per year. Specific yields of the silty sand approxi- mate seventeen percent (17%) to eighteen percent (18%). The majority of the soil encountered consists of clean, fine- to medium-grained sands. These materials have permeabilities of approximately five hundred (500) to six hundred (600) feet per year and specific yield of twenty-four percent (24%) to twenty-four and one-half percent (24-1/2%). Inter- mediate silty sands have approximately fifteen percent (15%) fines, permeabilities of two hundred seventy (270) feet per year, and specific yields of twenty percent (20%) to twenty-two and one-half percent (22- 1/2%). The bedrock encountered consists mostly of sandstone of the Laramie Formation. Claystone members of the Laramie Formation were encountered throughout portions of the site, and interbedded siltstones, claystones, and sandstones were also encountered. In general , it is anticipated that the sandstones are moderately to highly permeable; the claystones are relatively impermeable; and the interbedded siltstones, claystones, and sandstones have variable permeabilities depending on the amount of sandstone, siltstone, and claystone encountered. The bedrock was encountered at relatively shallow depths of approximately ten (10) to twenty (20) feet over the majority of the site. However, depths of thirty (30) to forty (40) feet were encountered in the south-central • portion and in the northwest corner of the site. Bedrock was not encoun- tered to depths of seventy-five (75) feet in the southern portion of the property along the western edge, which is in the Crow Creek flood plain. -6- 7 GENERAL COMMENTS It should be noted that the test borings were drilled on approxi- mate one (1 ) mile grids and that variations in the soil and groundwater conditions could have occurred between these test borings. -7- r APPENDIX A. r TEST BORING LOCATION PLAN. NI • ,�ilq4 IJc..t4 X1O.6�1'" f�lo.5 ® O 0 014 15 14 5�/L.i< n.13 No.7 ' Nom LID.f_ 1" =5000' G 1 22 23 24 i1 V 0.15 ' No.I2 No.a No.3 0.2_ R64W R63W 2.9 28 27 26 Al.! KID.2 Z � No.2 i too.I G Isis,,_11 _o_�? 31 32 33 . '0 kt\ i\‘‘d No.23 AIo.20 No.17 No.1O T b N E O ® 1 T 5 N • 1 - 6 5 47 19 tN 12 'Jo.25 O LL- OTC.i BORINGS NOT bRILLis . A-2 EMPIRE LABORATORIES, INC. r KEY TO BORING LOGS ��e., TOPSOIL �•�� GRAVEL roomo AA. FILL •���� SAND& GRAVEL ^wow�/� SILT •i• SILTY SAND & GRAVEL .1 .� e/e CLAYEY SILT ,°p COBBLES o , i. e SANDY SILT SAND,GRAVEL& COBBLES ro �. CLAY o WEATHERED BEDROCK mom Pir SILTY CLAY __ SILTSTONE BEDROCK i �d SANDY CLAY CLAYSTONE BEDROCK SAND • • • SANDSTONE BEDROCK �•• SILTY SAND NIKE. �• • MINI LIMESTONE i. . ■M Prig CLAYEY SAND XxX GRANITE XXX ' SANDY SILTY CLAY Ill ill SHELBY TUBE SAMPLE ElSTANDARD PENETRATION DRIVE SAMPLER WATER TABLE 24-48 HRS AFTER DRILLING C HOLE CAVED 5/12 Indicates that 5 blows of a 140 pound hammer falling 30 inches was required to penetrate 12 inches. A-3 EMPIRE LABORATORIES, INC. • LOG OF BORINGS • CsUPTE-I No. I No. Z No.3 l.Jo. 4 • 10/12 4.>'. 1R/124 - • 4/12-1 . : ' 1Q/12��/j;447-49/1? K/O 4/12 , :• •. •• • 97/123••• 15/12 10 17/12 12/12 j•• •' 25/1? •• Y •. 13/121-1 . . • 1. 17/12 T" 14/12 3. ". • 20 46/12h 28/127.1: A-a EMPIRE LABORATORIES, INC. I LOG OF BORINGS • QE,PTN Mo. 6 No. 7 No.B N-lo.9 0 16/12 ')v 19/12 11/12x"'" 8/12.. •• ' . . 4/12 �.- 6/125 .- • 4/1?�' ••• 4/12.: • • • • •p 14112 1,1 6/12[IF • 17/]2 t3/1?j'• .. . 26/12 33/12 -] - _ 6/12 12/12D. •-:- -- 1------1 20 20/12 ___ I 22/12h • . 50/10 - 30 • A-5 EMPIRE LABORATORIES, INC. 0 LOG OF BORINGS DE_PTI-4 ND. ►O Na. l 1 No. 12 K10. 13 0 6 12 = ' 2 7/12�.'� 7/12 18/1 i I • l; 8/12 • 10/1211. •1" 7/12 3•• .• 5/12 •' 10 12112 =-- • 30/12D • • I 8/12tj:•.• 20/12 : : . 19/12h • 50/1 50/12 - 50/6 • 20 50/4 • • A-6 • • - EMPIRE LABORATORIES, INC. • r r • LOG OF BORINGS bf_.PTF-1 t•--10. l4 fvo. ►5 t.lo.16 MO 17' 0 . 6 12 F 6 2 =ter 12 12 . .: 2 2 = 12 12 9 12 ". •• • _ 8/12='•' - 10 5 12 °• 1 16 12 . . 11 12 • 15 12 2: 2 21 12 19 12 = 8 12 . •• •I 20 s = • -. I ._ 28 1213 '- ' 50 6 19 12 = : • . 47 12 . • ' • 21 12 = • 30 • " I 1 , - 23 1213. 47 12 .; 50 3 • .. 3312 . • - • 40 50 10�: � • 50 50/9 A-7 EMPIRE LABORATORIES, INC. In a • LOG OF BORINGS • bLP1 -1 t.-Jo.18 k10.19 No.20 No.21 0 6/12 04' 7/1? 12/12 ;f''' 15/121' '' .• � / / • 5/12 ' . 9/12 = ••• • 3/12 -7- 4/12�/ • 10 4/12 a:. • 9/12. •• ••• 4/12a: I 20/12 34/12-, : : 11/12 0'1 -* 9/12 3 41/121=1--j• • • 20 50/10 I 14/123 50/9 ?4/17 ;• 30 • 35/1? J•- - 40 50/4 • EMPIRE LABORATORIES, INC. • LOG OF BORINGS DEPTH t-/o.23 NM..24 Llo.Z5 0 21/12 Vrttl 11/17 J:�V T4/1? •-•. I-•.• • . I 10/12 1a • 7/12 15/17 = • 10 6/12 - • 25/122 : 12/12 H. • . : 11/12 � 22/12 • • 9/12 . : • I 20 6/12 3. - 47/12 3 /12 bi-. : 12/12 • : I 30 17/12 • • 50/17 �. O 40 43/12 s.. - 2• • . 50 35/12 • i• • 60 30/12 �'• I 70 O . . 50/11 � ' EMPIRE LABORATORIES, INC. • APPENDIX B. 03NIdl3a 1N3J b3d O O N � Q � �O � CD U p ^ O O � _ _ _ _ -- _ _ — — __ — — — CV \ __ _— _ — _ _ — _ _ _ — — _ � —� __ —� __ — _ _ _ -- - - - _ — \ _ —_�_ __ _— _— _ _ _ — _ _ n __ __ — _ — _ -- _ — __ - - - - _ — O . � � — — _— —— — — � _ —_ —_ _ — _ — � W � � � � � � V o o � � ZN — _ _ _ _ — — — — — — — _ _ — _ — — � � w � ~ r � J u � _ � _ � � � � _- �� � � __ _ _ � - � I�/ � Z Vi � ~ � N t1� �o — — -- — - -- -- - - — -- - - — � � N I z � � — —— — — — — — —— —— — — — N � — z N � O z o . 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U c, O J - O O n .0 to V O M CO V O O O P co ONISSVd 1N3D bad B-7 EMPIRE LABORATORIES, INC. - 1 • • a3NIV1321 1N3D 213d • O N M •cr CO O O 0 a O _ —— —— — —— —— —— — LJJ J �k Lj CZ tra CD U o N • v)I 4t LLJ - N z 0 N — — —— —— — — — — — — — — — — — •r— S- 0 W J d L1) O U- O Z LL, o ^' N Q w 1 V N 0 0 0 0 0 0 0 0 0 O P DD `O v) Q M N ONISSVd 1N3D 213d B-8 EMPIRE LABORATORIES, INC. r • • PERMEABILITY I • LOCATION OF SAMPLE: Boring 2 @ 3.5'-4.5'• I TEST PROCEDURE- Falling Head Method I DENSITY: 98.81/Ft3 PERMEABILITY: k = 127.3 Ft/Yr _ I 2000 . . 1600 y . i , _ I al 200. r I L _J Q g 800 W 400 I I 0 0 .04 .08 .12 .16 .20 TIME - HOURS I I I B-9 EMPIRE LABORATORIES, INC. - r PERMEABILITY LOCATION OF SAMPLE: Boring 3 @ 3. 5'-4. 5' TEST PROCEDURE:_Fal 1 i ng Head Method DENSITY: 103.1#/Ft3 PERMEABILITY: k = 32.8 Ft/Yr • 250 200 2 1 ci 150 } J 100 . a 50 0 0 1 2 TIME - HOURS B-10 EMPIRE LABORATORIES, INC. PERMEABILITY LOCATION OF SAMPLE: Boring 9 @ 13.5'-14.5' • TEST PROCEDURE. Fal 1 i ng Head Method DENSITY: 103.4#/Ft3 PERMEABILITY: k = 269.3 Ft/Tr 5000 4000 c3000 • >- >- Fri 2000 n. 1A1 6 ` 1 000 0 0 .05 .1 .15 .2 .25 TIME - HOURS B-11 EMPIRE LABORATORIES, INC. • PERMEABILITY LOCATION OF SAMPLE: Boring 15 @ 3. 5'-4.5' • TEST PROCEDURE. Falling Head Method DENSITY: 103.5#/Ft3 PERMEABILITY: k = 35.3 Ft/Yr • 4000 ..3000 >- Of] X2000 W 1000 • 0 -'J�--- 0 .4 .8 1 . 2 1 .6 2.0 TIME - HOURS • • B-12 EMPIRE LABORATORIES, INC. • • PERMEABILITY• LOCATION OF SAMPLE: Boring 17 @ 13.5'-14. 5' TEST PROCEDURE• Fall i ng Head Method DENSITY: 102.7#/Ft3 remolded sampl e PERMEABILITY: k = 549.1 Ft/Yr I • 1500 1200 a 900 � I 6 600 1 300 0 _ 0 .03 .06 .09 .12 .15 TIME - HOURS 8-1.3: EMPIRE LABORATORIES, INC. t PERMEABILITY LOCATION OF SAMPLE: Boring 25 @ 13.0'-14.0' • • TEST PROCEDURE• Falling Head Method DENSITY: 101 .7#/Ft3 PERMEABILITY: k = 573. 3 Ft/Yr 5000 4000 li .3000 } . IL I- I _ m W X2000 W . 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CO CO CO CO CO CO O Cr) Ch CO CO CO O CO Ch CO CO Ch CO N CO CO Cr LC) h . r r r- r r 4-) C 0 U' U 0 Z N N N m 8-23 r r • SUMMARY OF TEST RESULTS Atterberg Summary Boring No. 15 16 • Depth (Ft. ) 3.5-4.5 3.5-4.5 Liquid Limit 16.1 32.4 Plastic Limit 17.1 14.0 • Plasticity Index N.P. , 18.4 Passing 200 28.3 68.3 Group Index 0.0 9.9 Classification Unified SM CL AASHTO A-2-4(0) A-6(10) • 8-24 • SUMMARY OF TEST RESULTS Boring 2 @ 3. 5'-4.5' Atterberq Limits II Liquid Limit 20.1 Plastic Limit 13.5 Plasticity Index 6.6 % Passing #200 36.4 Group Index 0.3 Classification • Unified SM-SC AASHTO A-4(0) Permeability: k = 127.3 Ft/Yr @ 98.8#/Ft3 Dry Density Boring 3 @ 3. 5'-4.5' Gradation Sieve Size % Passing #4 100 #10 99.9 #20 99. 8 #40 99.3 . #60 92.4 #100 67.5 #200 31 .3 Permeability: k = 32. 8 Ft/Yr @ 103.1#/Ft3 Dry Density Specific Yield: 17% approximate 11..9R SUMMARY OF TEST RESULTS Boring 9 @ 13.5'-14.5' Gradation Sieve Size % Passing_ #4 100 #10 99.8 #20 99.8 #40 99.4 #60 91 .8 #100 46.5 #200 14.6 Permeability: k = 269.3 Ft/Yr @ 103.4#/Ft3 Dry Density • Specific Yield: 22. 5% approximate Boring 14 @ 13.5'-14.5' Gradation Sieve Size % Passing 1/2" 100 3/8" * 99.3 #4 97.3 _ #10 95.0 #20 92.7 #40 84.6 #60 61 .4 #100 23.9 #200 9.1 • Specific Yield: 24% approximate B-26 . SUMMARY OF TEST RESULTS Boring 15 @ 3. 5'-4.5' Gradation Sieve Size % Passing 3/8" 100 #4 99.8 #10 98.9 #20 96.8 #40 91 .4 #60 79.7 #100 51 .4 #200 23.7 Permeability: k = 35.3 Ft/Yr @ 103. 5#/Ft3 Dry Density Specific Yield: 18% approximate Boring 17 @ 13. 5'-14.5' Gradation Sieve Size % Passing #10 100 #20 95.2 #40 74.5 #60 46.6 . #100 16.4 #200 6.7 Permeability: k = 549.1 Ft/Yr @ 102.7#/Ft3 Dry Density Specific Yield: 24.5% approximate B-27 F SUMMARY OF TEST RESULTS Boring 23 @ 23.5'-24.5' Gradation Sieve Size % Passing 3/8" 100 #4 99.8 #10 99.1 • #20 75.8 • #40 59.9 #60 44.5 #100 22.8 #200 7.8 Specific Yield: 24.5% approximate Boring 25 @ 13.0'-14.0' Gradation Sieve Size % Passing #4 100 #10 99.9 #20 97.0 #40 88.2 #60 75:7 #100 38.4 #200 9.5 Permeability: 573.3 Ft/Yr @ 101 .7#/Ft3 Dry Density Specific Yield: 24. 5% approximate B-28 Hello