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Home My WebLink About20071165.tiff PRELIMINARY DRAINAGE STUDY FOR SORRENTO ADDITION MEAD, COLORADO • Prepared For: Ken Williams & Ted Drysdale Liberty Properties LLLP 4068 Camelot Circle Longmont, Colorado 80504 February I, 2007 Project No. LIBERP-7A880 I-00-202 Landmark Engineering Ltd. 352 I West Eisenhower Boulevard Loveland, CO 80537 2007-1165 �gy'�, y`k' x `u tr A Way uaT^'. *t 6 y Ot tandmarkK .4,` February I, 2007 Project No. LIBERP-7A8B01-00-202 Ms. Sandee Miller, P.E. Town Engineer C/O Town of Mead 441 Third Street Mead, Colorado 80542 RE: Preliminary Drainage Study for Proposed Sorrento Addition Bordering Weld County Roads 5 and 32, Weld County Colorado Dear Ms. Miller, This letter transmits the Preliminary Drainage Report referenced above. Information has been presented based on the Town of Mead's Storm Drainage Criteria and Construction Standards, dated January, 1998. If you have any questions regarding the above information, please contact me. Sincerely, LANDMARK ENGINEERING LTD. Reid W. Bond, P.E. RWB/tv Attachments TABLE OF CONTENTS Page No. SECTION I — GENERAL PROJECT LOCATION AND DESCRIPTION General Legal Description I-I General Location and Adjacent Subdivision Developments I-I Existing Site Description I-I SECTION 2 - DRAINAGE BASINS AND SUB-BASINS Major Basin Description 2-I Historic Drainage 2-I Offsite Drainage 2-2 Onsite Drainage 2-3 SECTION 3 - DRAINAGE DESIGN CRITERIA Site Constraints 3-I Hydrological Criteria 3-I Hydraulic Criteria 3-2 SECTION 4 - DRAINAGE FACILITY DESIGN General Concept 4-I SECTION 5 - EROSION AND SEDIMENT CONTROL Erosion and Sediment Control 5-I SECTION 6 - CONCLUSIONS Conclusions 6-I LIST OF REFERENCES FIGURE I - Location Map APPENDIX Historic Analysis Developed Analysis Background Information PRELIMINARY DRAINAGE STUDY FOR SORRENTO ADDITION MEAD, COLORADO CERTIFICATION OF ENGINEER I hereby affirm that this Preliminary Drainage Study for the Sorrento Addition was prepared by me, or under my direct supervision, in accordance with the provisions of the Town of Mead for the responsible parties thereof. To the best of my professional knowledge and belief, it meets or exceeds the criteria for the Town of Mead's Drainage Requirements. Reid W. Bond, Registered Professional Engineer State of Colorado No. 29647 \,��`��Pp0 REG/gT//, 29647 Y� '.4 .. 2(;:t,÷, /�///4/.110NA"cc- SECTION I GENERAL PROJECT LOCATION AND DESCRIPTION General Legal Description The site is located within the Northwest 1/4 of Section 21, Township 3 North, Range 68 West. It contains approximately 158 acres. General Location and Adjacent Subdivision Developments The site is bordered on the North by Weld County Road (WCR) 32, on the west by WCR 5, on the east by the Great Western Railroad and on the south by crop land. See the attached site plan drawing. No major open channels, lakes, streams or other water resource facilities exist on or adjacent to the site. Two subdivisions are located within 1/2 mile of the site. Eden's Reserve Subdivision is located approximately 1/4 mile east, and the Hunters Ridge Subdivision is located approximately 1/2 mile east of the site. Existing Site Description The existing site contains approximately 158 acres. With the exception of a barn and house located on the northwest edge of the property, the site consists of irrigated crop land. Drainage is generally from north to south with the highest elevation of 5042 at the north central boundary and the lowest elevation of 5008 at the southwest corner of the site. Overall site slope is approximately 1.2 percent down to the south. A slight ridge runs from the north central to the southeast corner side of the site. Drainage to the east sheet flows over crop land to a 1-1/2 foot deep drainage ditch paralleling the Great Western Railroad tracks located adjacent to the site's east boundary. Drainage continues 1-1 south in the railroad ditch, eventually reaching the Liberty Gulch drainage way. Site drainage to the west sheet flows south-southwest. Some drainage is to the east drainage ditch for WCR 5, then south, paralleling WCR 5 to the Liberty Gulch drainage way which is located approximately I/4-mile south of the site. Significant storm event runoff may over top WCR 5 and flow west to Liberty Gulch or may flow around the east side of a residence located just south of the site, then south to Liberty Gulch. Soils Conservation Service information shows onsite soils consisting of Nunn Clay Loams and Wiley-Colby Complex (Silt Loams). The Nunn Clay Loams cover approximately 30 percent of the site, extending from the northwest to the south central portion of the site. The Wiley- Colby Complex soils are located over the remainder of the site. Soils tests performed in April, 2005, encountered water from 6 to 12-feet below the surface. Privately owned concrete lined irrigation ditches and a 0.7 acre irrigation holding pond border the site's south boundary and act as a barrier to any onsite runoff. In addition, approximately 600 feet of concrete irrigation ditch is on the north boundary of the site. This north ditch supplies water for onsite irrigation and for a private 9-inch buried steel irrigation transmission line that traverses the site from north to south. No significant drainage ways exist on the site. Surface waters generally sheet flow to the southeast and southwest corners of the site then follow existing drainage ways to the Liberty Gulch drainage (see site map). The Liberty Gulch drainage flows from the northwest to the southeast, eventually reaching the St. Vrain Creek located approximately 3.5 miles south- southeast of the site. Multiple utilities border the north side of the site. The Northern Colorado Water Conservancy District has a 28-inch raw water transmission line located approximately 75 feet south of WCR 32. The Little Thompson Water District has a 6-inch water main on the north edge of WCR 32, Xcel Energy has a 12-inch high pressure steel gas line in the middle of WCR 32, Anadarko has a high pressure steel gas line paralleling the south right-of-way of WCR 32, 1-2 and a buried telephone line is located on the south side of WCR 32 as is an overhead electrical line. The proposed development includes a 175 home subdivision and restaurant/recreation center. Housing lots will be approximately 1/2 acre. All internal roads will be paved. Water utilities will be provided by the Little Thompson Water district. Wastewater facilities will be provided by the St. Vrain Sanitation District. Natural gas will be provided by Xcel Energy. Telephone service will be provided by Qwest. 1-3 SECTION 2 DRAINAGE BASINS AND SUB-BASINS Major Basin Description The site is located in a rural area of Weld County and is within the South Weld County 1-25 Corridor Master Drainage Plan. The basin's drainage is to the southeast, flowing to the South St. Vrain Creek which is tributary to the South Platte River. Discussions with Weld County Public Works personnel indicated that the Master Drainage Plan north of St. Vrain Creek has not yet been approved by the County. The site is located approximately 3.5 miles north of the St. Vrain Creek and is approximately 25 feet above the Liberty Gulch Drainage. As such, no 100-year flood plains or floodways affect the property. No major irrigation ditches or laterals are influenced by this site. A small concrete lined irrigation ditch is located offsite and adjacent to the south property line. The ditch serves crop land located south of the site. A small privately owned concrete lined irrigation ditch is located on the north site boundary. This 600- foot long ditch receives water from a small irrigation ditch located north of WCR 32, and is used to convey water to the site. It also supplies water to a private, gravity flow 9-inch steel buried transmission line that delivers water to a 0.7 acre holding pond located offsite and adjacent to the south boundary of the site. Current plans call for rerouting this transmission line around the north and east sides of the site. Historic Drainage Historic drainage is shown on the drawing enclosed in the pocket folder entitled, "Preliminary Drainage Study, Drainage Exhibit, Historic Condition." Onsite historic drainage is split by a small ridge that runs from the north central to the southeast end of the site. Drainage to the east flows to a 1-1/2 foot deep drainage ditch paralleling the railroad tracks bordering the east 2-1 side of the site. Drainage continues south down the railroad track ditch, eventually reaching the Liberty Gulch drainage way. Site drainage to the west flows south-southwest to a drainage ditch paralleling the east side of WCR 5. Small storm event runoff flows south to the Liberty Gulch drainage located approximately 1/4 mile south of the site. Large storm event runoff may overtop WCR 5 and flow west down a small gully to the Liberty Gulch drainage, or may flow around the east side of a residence located just south of the site, then south to Liberty Gulch. Offsite Drainage Offsite drainage includes approximately 251 acres of crop land located north of the site in the West 1/2 of Section 16. Storm runoff flows in a southerly direction until it reaches WCR 32, then flows either east or west from a high point located approximately 530 feet east of the WCR 5 and 32 intersection. Eastward flows from 231.8 acres go towards two 18-inch culverts that cross WCR 32. During significant storm events (201 cfs for a 100-year storm event), the culverts are not adequate and excess runoff flows past the culverts to the southeast end of the subbasin, eventually overtopping WCR 32 and flowing south onto the northeast end of the Sorrento Addition property. Runoff going west from the WCR 32 high point comes from 19.2 offsite acres and flows to the northwest corner of the WCR 5 and 32 intersection. Irrigation piping is located at this intersection that convey flows east under WCR 5, then south to the southeast corner of the intersection and cropland. Onsite development will require conveyance of the offsite storm runoff through the site to the detention basin discharge. Two storm drainage culvert crossing locations are proposed under WCR 32. One crossing will be at the northeast corner of the site and will discharge to a proposed drainage swale. The second will be located at the northwest corner of the site and will convey waters to a proposed storm sewer that will convey both storm water runoff and 2-2 irrigation water to the southwest detention basin. The irrigation water will be used for non- potable irrigation of subdivision outlots. A third culvert may be installed 530 feet east of the WCR 5 and 32 intersection. This culvert would replace an existing culvert that conveys irrigation water from north to south across WCR 32. This culvert is located at the high point of WCR 32 and has little or no stormwater conveyance capability. Onsite Drainage Anticipated onsite drainage is shown on two drawings enclosed in the pocket folder entitled "Preliminary Drawings Study , Drainage Exhibit, Developed Condition". Proposed grading contours have not been developed. As a result, the drawings show existing contours plus anticipated major drainage subbasins, drainage flow arrows, streets, drainage swales, inlets, storm sewer piping, detention ponds, and outlet locations. Final site grading will establish building top of foundation elevations that allow 2 percent or greater slopes away from homes to streets and drainage swales. Site runoff will be conveyed by streets, storm sewers or drainage swales to three detention basins. The northeast and southeast detention basins discharge to a drainage swale that will also convey the majority of offsite storm runoff to the southwest detention basin. The southwest detention basin outlet will either discharge west under WCR 5 to a drainage swale that goes to Liberty Gulch or south around the east side of a residence to the east side of WCR 5 and to Liberty Gulch. Because 221 cfs of offsite 100-year storm event runoff must be passed through the site to the discharge point of the southwest detention basin, attention will have to be given to downstream conveyance features. Discussions and meetings with the Town's Engineer, Weld County Public Works Department personnel, and adjacent property owners will be required to determine the final discharge drainage routing and required improvements. 2-3 SECTION 3 DRAINAGE DESIGN CRITERIA This drainage study was prepared in accordance with the Town of Mead's Storm Drainage Criteria, dated January, 1998. Site Constraints This study was prepared for a 158 acre site that currently exists as irrigated cropland. No site constraints exist due to existing slopes or existing streets. Onsite to offsite drainage constraints include the Great Western Railroad tracks on the east boundary, concrete irrigation ditches paralleling the south boundary and WCR 5 on the west boundary. An existing house with outlot structures located on the northwest corner of the site will be demolished or removed from the site. Existing utilities that run parallel to WCR 32 include water mains, gas mains, telephone and overhead electric. Buried utilities will provide challenges for the offsite to onsite drainage which will enter the site under WCR 32. Final drainage design will require pot-hole locates to define the horizontal and vertical locations of existing buried utilities and to determine the best means for crossing them. Hydrological Criteria Rainfall intensity was determined using formulas that provide results that approximate the Town's rainfall intensity curves. The site falls within the area depicted by Figures RA-I through RA-12, Rainfall Depth-Duration-Frequency curves found in Volume I of the Urban Storm Drainage Criteria Manuals. The information from these figures was used in conjunction with formula RA-3 to determine rainfall intensities for runoff calculations. Runoff calculations were performed to determine flows for historic 5-year and developed 100- year recurrence intervals. Calculation methods included both the Colorado Urban Hydrograph 3-1 Procedure (CUHP), and the Rational Method. The CUHP program was used to determine offsite historic 5-, 10-, and 100-year flows and the 5-year historic flow for the onsite west subbasin. These areas were larger than the 90 acre maximum that is recommended for using the Rational Method. The Rational Method was used for the northeast and southeast developed condition subbasins that were less than 90 acres. Runoff coefficients were developed using spreadsheets and impervious values derived from Tables RO-3 and RO-4, Figure RO-5, and formula RO-7 of the Urban Storm Drainage Criteria Manual. Detention storage calculations were based on the Rational Formula-Based Modified FAA Procedure, using a spreadsheet to derive the maximum volume of storage needed. Water Quality Capture Volume and outlet requirements have not been performed for this study but will be calculated in accordance with Section 3.4.3. of the Urban Storm Drainage Criteria Manual for the final drainage report. Hydraulic Criteria Because developed site grading has not yet been performed, hydraulic calculations for flows in curb and gutters, inlets, storm sewers, and drainage swales have not been performed. One exception is for the drainage swale bordering the east and south sides of the site. The width and slope of this swale was determined using a flowmaster v.6.1 program to insure adequate conveyance could occur for 100-year offsite flows plus releases from the northeast and southeast detention basins. When developed site grading is completed, hydraulic calculations will be performed using flowmaster v.6.1 and Storm CADD software programs. Results will be tabulated for ease of review in the final drainage report. 3-2 SECTION 4 DRAINAGE FACILITY DESIGN General Concept The existing site is currently being used as irrigated crop land, having historic sheet flow drainage from north to south. No major drainage ways are present for stormwaters to enter or exit the site. By virtue of the area topography, historic offsite storm drainage enters the site from approximately 251 acres of irrigated crop land from the north. Minor storm event offsite runoff enters the site through two I8-inch culverts crossing Weld County Road 32. Major storm event drainage would most likely overtop WCR 32 and sheet flow onto the site. The Town's storm drainage criteria requires storm drainage facilities for residential areas be investigated for 2-year and 100-year storm events. The 2- year event evaluation is to consider minimizing inconvenience, protecting against minor damage and reducing maintenance costs due to stormwater damage at reasonable costs. The 100-year event evaluation is to eliminate substantial property damage or loss of life. In addition, the criteria requires all storm water detention facilities to be designed to detain storm water runoff from a fully developed subdivision for a 100-year storm event, with release of the detained water not to exceed the quantity and rate of a 10-year storm falling on the undeveloped site. At this conceptual stage, final site grading has not been performed, and hydraulic analysis of street gutters, drainage swales, storm sewers and inlets cannot be done. However, the major subbasins have been determined and the directions of runoff has been sufficiently defined to allow preliminary sizing of the detention basins using the Rational Formula-Based Modified FAA Procedure. In addition, the sizing of the drainage swale paralleling the east and south sides of the site has occurred to insure adequate slope is available from the northeast site corner to the southwest detention basin. This swale will convey onsite runoff from the northeast, southeast and south areas, and will also convey the majority of the 100-year event offsite runoff, estimated at 201 cfs. 4-1 Although the Town allows a detention basin release rate equal to the 10-year storm falling on the undeveloped site, initial sizing attempts have been made to achieve release rates approaching the 5-year storm event. Releases from the subdivision will be to land under Weld County's jurisdiction, and the County's required release rate is the 5-year storm event. Future discussions with the Town and County will occur to clarify the final release rate requirements. As mentioned previously, two options exist for the discharge from the southwest detention basin. One option is to discharge to the south, staying on the east side of WCR 5. This discharge route would most likely be on the east side of an existing lot containing a home and outlot buildings, then south on the east side of WCR 5 to Liberty Gulch. The second option is to discharge to the west under WCR 5 to a drainage swale that would flow to Liberty Gulch. This option would require enlargement of the existing drainage ditch or construction of a new drainage swale from WCR 5 to Liberty Gulch. Because both discharge routes are in the County's jurisdiction and will impact private landowners, meetings involving County personnel, Town Engineer, and landowners will be needed to make a final route determination. Before the next drainage report submittal, site grading will be completed and hydraulic calculations for runoff conveyances will be performed to insure that the Town's stormwater criteria is met. In addition, detention basin discharge routing will have been resolved to show conveyance routing and sizing to Liberty Gulch. 4-2 SECTION 5 EROSION AND SEDIMENT CONTROL Site development has the potential for causing localized erosion and subsequent deposition of sediment offsite. Significant storm event runoff for this site will flow to the southwest and southeast corners of the site and will have the potential for filling or plugging existing drainage ways and causing property damage. Wind blown sediment can fill adjacent irrigation ditches causing problems with farming operations. Erosion control will include minimizing soil exposure, controlling runoff across exposed areas, and capturing sediment. Recommended erosion control measures are presented below. Minimizing Soil Exposure: Where practical, soils exposure should be kept to a minimum. Because most of the site will be impacted by overlot grading activities, these activities should be completed in a very short time frame. Areas not scheduled for immediate development should be fertilized, reseeded, and crimped and mulched with straw to protect exposed soils until vegetative cover is established. Controlling Runoff Across Exposed Areas: With the exception of drainage swales, site conditions will promote sheet flow runoff across much of the site. Where drainage swales are constructed, wattles should be installed and maintained. In addition, inlet protection using straw wattles and/or gravel filters should be utilized to avoid sediment entry into newly constructed storm sewer systems. Use of temporary drainage swales and temporary detention basins may be required if site development occurs in phases. Maintenance of the temporary facilities will require inspection, repair and sediment removal after significant storm events. Capturing Sediment at Site Boundaries: To avoid sediment transport to offsite areas downhill from the site, sediment capture in the form of silt fencing should be installed on the south boundary and on portions of the east and west boundaries. In addition, graveled entryways should be provided where they are adjacent to paved roadways. 5-1 Dust Control: Dust control may be required for onsite disturbed areas during site development activities and may include watering as needed on unpaved roads and disturbed surface areas, controlling vehicle speeds, creating furrows at right angles to the prevailing winds and compaction of disturbed soils on a daily basis. Erosion control measures will be prepared and shown on a separate exhibit for the final drainage report. The erosion control measures will also be included in the development civil construction drawings. Because of the size of the development, the state required Air Pollutant Permit, Stormwater Discharge Permit and Dewatering Permit (if applicable) will be obtained and a Storm Water Management Plan will be prepared. 5.2 SECTION 6 CONCLUSIONS This preliminary drainage study has identified offsite and onsite historic drainage directions and runoff quantities. In addition, it has provided initial information regarding developed onsite major subbasins, detention basin sizing and locations, and the routing for conveying storm- water runoff from offsite and onsite subbasins. The information indicates that the final drainage plan can satisfy the Town of Mead's Storm Drainage Criteria. The release of detained onsite stormwater plus offsite pass-through runoff will be discharged at the southwest corner of the site. The routing direction for the discharge through offsite properties will need to be resolved during site design and will be presented in the final drainage report. 6-1 LIST OF REFERENCES • Town of Mead's "Storm Drainage Criteria and Construction Standards", prepared by the Sear-Brown Group and dated January, 1999. • Weld County Storm Drainage Criteria, Proposed Addendum CO the Urban Storm Drainage Critera Manuals Volumes 1,2,3, prepared by Weld County Public Works Department, 1 1 1 1 H Street, Greeley, Colorado, February 2006. • Urban Storm Drainage Criteria Manuals, Volumes I, 2 and 3, Urban Drainage and Flood Control District, Denver Colorado, June 2001. • Flowmaster v6.a Softwater Program, Haestad Methods, Inc, 37 Brookside Rd., Waterbury, Ct. USA. g //.�•. - __ v L PROJECT LOCATION v• �sa� it , I ar-srz ur •TER It I .: n • � � �. _e.. II? —._ fan'• _, - 4 L� I l� .N t� Y t '- " 1AiAYlvlx I I Ns' II..'11p '4U ♦ '� [I Lx5 lit f1 ,,,mr,tl�.,,rdlr, TITLE: SORRENTO ADDITION SITE LOCATION S I4f>I10200 t U W EEr®DbUIEIEtaoc9118 ENGINEERS/ARCHITECTS/PLANNERS/SURVEYORS CLIENT: LIBERTY PROP. LLLP SCALE: 1 = 1 MILE 3521 Wesl Eisenhower Blvd., Loveland, Colarodo 80537 (970) 667-6286 Denver (303) 629-7124 Fax (970) 667-6298 FEB 1, 2007 JOB #: LIBERP 5E7F-01-203 HISTORIC ANALYSIS Sorrento Addition Off-Site North Subbasin Flows: 100. 10 and 5 Year Printouts for User Selected Storm Hydrographs flow in cfs m a u o 0 0 0 7 .- N f E z z z z z z c ^ d w u a a a in N y N E .. O p V 0 O O 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 10 0 0 0 0 0 0 15 0 0 0 0 0 0 20 1 5 2 0 1 0 25 17 20 9 4 4 2 30 55 38 20 11 6 3 35 101 54 30 16 7 4 �tG 40 142 64 37 18 7 4 fr q 45 171 70 41 20 7 4 1-'L �''/5�Ex�,'tD 50 189 72 42 20 7 4 F 55 198 72 42 19 6 4 60 201 69 40 19 6 3 l KA-1 Al. -- ✓s 65 ' 197 66 37 18 6 3 1-� rLO 70 9 188 63 34 17 s 6 3 AXIITaAaG� 80 168 56 29 14 85 157 55 27 13 5 2 2 li 90 145 51 25 12 4 95 134 48 23 11 4 2 100 124 45 22 10 3 2 105 116 42 20 9 3 110 109 39 19 8 3 115 101 36 18 7 2 120 95 34 17 6 125 88 31 15 6 2 130 82 29 14 5 2 135 75 26 13 5 2 140 69 24 12 4 2 145 63 22 11 4 - 150 57 20 10 4 155 52 19 9 3 160 49 18 8 3 165 45 16 8 3 0 170 43 15 8 3 0 175 40 15 7 2 0 180 38 14 7 2 0 185 35 13 6 2 0 190 33 12 6 1 0 0 195 31 11 5 1 0 0 200 29 10 5 1 0 0 205 27 9 5 1 0 0 210 25 9 4 0 0 0 215 23 0 4 0 0 0 220 21 7 3 0 0 0 225 19 6 3 0 0 0 230 17 6 3 0 0 0 235 15 5 2 0 0 0 240 12 4 2 0 0 0 245 10 3 1 0 0 0 250 8 3 1 0 0 0 255 6 2 1 0 0 0 260 4 1 0 0 0 0 265 3 1 0 0 0 0 270 2 1 0 0 0 0 275 1 0 0 0 0 0 280 1 0 0 0 0 0 285 0 0 0 0 0 0 290 0 0 0 0 0 0 295 0 0 0 0 0 0 300 0 0 0 0 0 0 CC CO 0) CD m•- r a) OOP- O a E r-') Lc) c-- CO V - 0 lO N ' to OG 0 I- G U ,_ Nv N co (`l r r N N O n v • O n C N E m u N ° Q o cn A to vm .- apn O ,- O N O N o0 Q d ^ c0 O N CO v v .5 %wt.: 0 c0 N v V) V- C N N O ( W v N a m '‘.0 tO w n O la y) c•) ) N cO U) N 0 yt moo .-' oo X U U W X C W ,C., ',1 v v (0 (0 t0 E CO c) Cl a) C)O) VI v_ v (OCOCO J y — r .- a)a)C) a .. v v v )C co t0 co co> co O 000 (00 N- w x 0 r m CO a, U a — (0 aoa, rnco 9 y, ^, U) U') U) V -.Y v y m E N N N r toEa 'E 3'- in N (0 (0 N 0 O C. a 0 C: CO (7) M (h c') n o A o 0 o c0 LO (0 in co d ', N N N CO cO (O C ^ r) c-, c•-, to to ^ O rt C (') c') cO N N N a IQ m a > r y) 10 a. v v d a) a) 0) .. 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OK 4 u LL V > C O 0 O O O O C O L D o O O O O c A U d U a0 E LL J Q - 0 0 0 0 0 0 _ 0 0 0 0 0 0 U y 606666 U J Q U O M (00000343 00 03 43 N T •t •U 0 0 00 0 0 0 0 y O N 0 0 0 0 ad Eou a d NO N N N N N p O O o O 0 0 t -4° d _ ' LL C d 88888E O 0 O 0 _ O y (0 t0 f'1 n f7 r) ▪ T.T.2 ' n N N V) N m ` ,1600060 • N d p L-5 N E c g 0 0 0 0 0 N N 7 0 0 0 0 0 o 0 0 0 0 0 n wd d c � n — N N N 43 „ c Z N N N N N cu w a E 0] 0 0] 0 0 0 • 0 0 0 0 0 0 0. 666666 O . N 'Y N e r) 0 0 0 0 0 0 L H o n n w▪ E E 0) 00) V) N O D „ N N N m m O W 0 0 0 0 0 0 o d E _ o N N N 0 0 0 O C c0) 0 0 0 0 03 .m E 0 0 0 0 0 0 m J Q ea > w to 'O w • y I o m o m - a A Qa a �m W W a W Q m to o c _ . )- to u_ , ).- to o o ' o O ' • 0.. • j ❑. U vt O i o 0 N o . -0r c uiww 3 E zzzzzz a a w0 W 000000 Sorrenlo Addition On-Site Historic Flows 1/31/2007 T. : .s. Printouts for User Selected Storm Hydrographs flow in cfs o o ai n N 7 w v d v h E i w w w v o a a, o _m _ u, U) to vl U) N C O q C 0 C C p C C O r O O .- O O 0 0 0 0 0 0 0 5 0 0 0 0 0 0 10 0 0 0 0 0 0 15 0 0 0 0 0 0 20 1 11 3 0 7 2 i)� 25 34 31 15 24 22 10' j/� 30 86 47 26 60 32 18 J t t f1 35 123 53 31 84 35 21 L-✓ 40 139 52 31 95 35 21 A v 45 140 48 28 95 32 19 )gl��PIA/A 50 134 44 25 91 29 17 x- 60 119 37 19 80 25 55 127 40 22 86 27 13 Al A �U .a tC' ." 65 111 34 17 75 23 11 ttr - 70_ 100 32 15 68 22 10 A 75 89 30 13 60 20 9 80 78 26 12 53 17 8 85 68 22 10 45 15 6 90 58 19 8 39 13 5 95 50 17 7 33 11 5 100 44 15 6 29 10 4 ,,,t7 105 39 13 6 26 9 4, f 110 34 12 5 23, 8 3 - 115 30 10 5 20 7 3 120 26 9 4 18 6 3 125 23 8 3 15 5 2 130 20 6 3 13 4 2 135 17 5 2 11 3 1 140 13 4 2 9 3 1 145 10 3 1 7 2 1 150 7 2 1 5 1 0 155 5 1 0 3 1 0 160 3 1 0 2 1 0 165 2 1 0 1 0 0 170 1 1 0 1 0 0 175 1 0 0 0 0 0 180 0 0 0 0 0 0 185 0 0 0 0 0 0 190 0 0 0 0 0 0 1 m00000 n- E - 0 n o O m 0 o m ti m m r J N vmo ` T H O Y) N rl m i!1 N E O 0 ; N O LL N commNrva N N W N � CI LL y d O O - 0 0 W K u W - m 0 0 o 'o E c 0 O ! 00 2 D m m 1, N O�] tt ry ry 0. _ 2svn4nn N a 'E ¢ N m m '' 8t ° " " E m m Ns 3 E n c m m m o o m m m m m m v`3 m LLu I_ C C O J ry 3 E N (0 N vryi 7 U o o 0 o O a N re 0o w NNm m 5666606 u To V C C N E A o E CO a u' `a v E n c N m E a E ci r co m` •C n m a `v o = C C - co 7 E o m .o Q Z os m " 3www E . E E davv � TO E 2w60 inm O = 'oO H u000000 N N N N N N c000000 0 0 0 0 0 a . ' 000000 = 430. a u 9 LL U LL U C000000 0 0 0 0 0 C O > 2606060 au E 0 LL a J > 000000 0 0 0 0 0 0 • W000000 O O O O C 00 J 0 0 4 N 0 0 cJ of W T . 000005 y u v d 0 0 0 0 0 0 • p y 66666o O 0 6 C o E ❑ u Z. a a N N ON NN N N ? 660660 C ' C LL C • a O O O o O O p L 00 0 _ _ p • • C_ C 00 1666006 O O O G C a a L 6 U c 0 0 0 0 0 0 N y _ P O C p V O 3 y 0 0 0O o O • a• y C Cl m ci o • 0 0 0 0 0 0 u m E E CO _ o 0 0 0 0 0 o C 0 0 0 0 0 0 (O = p CU N N L 0 O NN CINv N 00000000 C E N N N N N 010000 ,50 • p u E _ c E I0 IO n n ❑ p _ E .qE 0 0 0 0 0 0 N a O > a N � N r• d ❑ N or E a E E ro a q ¢ CC oo' wawac E r w Q y w • C r w Y w o O. W86 > 86 , N a = ❑ p U . 0 E 0 G p • « - 000 a o o - Q C - a LLw N N N a0 E r m m m m Eti E win ti in emu, `p & J m O N ° 000000 Sorrento Addition 1/29/2007 Historic On-Site Imperviousness Areas WEST Area % Imperviousness (A) (I) A x I Paved 0.72 100 72.05 Roofs/Sidewalks-Driveways 0 90 0 Residential 0 43 0 Gravel Road 0.24 40 9.60 Turf 87.54 0 0 88.5 81 .65 (A x 1)/A 0.92 % Historic On-Site Imperviousness Areas EAST Area °A Imperviousness (A) (I) AxI Paved 0.00 100 0.00 Roofs/Sidewalks-Driveways 0 90 0 Residential 0 43 0 Gravel Road 0.34 40 13.60 Turf 71.92 0 0 72.26 13.60 (A x 1)/A 0.19 % DEVELOPED ANALYSIS 7 o N i { III i L , ti o I ' . cq I III eJ jilt r0 H a 12- o m \:,4N `., IV I j 0 H \ t41 cm mco 'L `.,3 { u ' O� r A T' o - m '- -, 0000000000 y o n o in o LP o In O Ill o - ry C V Q M M N N .-- ,- O O .14 •.C ` �� . 15 �u-awn�oq Z �'S .a 3 ZL1.1 a e R _fi p N :I� n N C� a E M NQm ]� g o - c co m w p r.-. CO M 'O C > --. .Q a) O] 9 N Q 0 6 V O t O ° F N Q o 1 N O N E ;� O V O E `am ^ � w o o p N Q p» ib p 0 m N ^ L > cn N C S W V- '. t in E o p in N in .In in Q ca M Qt0 '- lO o a N C N r N O N a) E `O M LO r E Q a U W O C D N -� hNN E in Q N Q o Q to l0 m m r- m rn C N r M O N ^ O M W r E . Q U) . O co Q �O pVj' Q O N fn w„1--- .z- N t0 (O N- O PI CO M a- CJ T vy. O O O O0 Q Q Q o 0 0 0 0 0 N (..7,p N cc Oti O `- tJ d�: N N M M p � N ,On O� ON IQ:If) � k] tfr' U N Project: Sorrento Addition -Preliminary Drainage Study-Northeast Project#: Objective: Detention Pond Volume Requirements 1'29/2007 Inflow Data: Design Storm 100 Year Drainage Area 26.45 Acres RIO Coeff(C) ass CxA 15.34 Off-Site Flow 0 cfs Time of Concentration 24.4 minutes Outflow Data: Design Storm 5 Year Discharge 11,10 cfs Comment: TIME CxA I Qin VOLin Ad'ust Ave Qout VOLout VOLtotal VOLtotal (min) (in/hr) (cfs) (cu fl) Factor* (cfs) (cu ft) (cu ft) (af) 10 15.34 7.15 109.69 65,813 1.00 11.10 6,660 59,153 1.358 15 15.34 6,10 93.58 84,222 1.00 11.10 9,990 74,232 1.704 20 15 34 5.30 81.31 97,569 1.00 11.10 13,320 84,249 1.934 25 15.34 4.70 72.10 108,154 0.99 11.10 16,650 91,504 2.101 30 15.34 4.25 65.21 117,384 0.91 11.10 19,980 97,404 2.236 35 15.34 3.85 _ 59.08 124,058 _ 0.85 11.10 23,310 100,748 2.313 40 15.34 3.55 54.47 130,727 081 11.10 26,640 104,087 2.39D 45 15.34 3.30 50.63 136,709 0.77 11.10 29.970 106,739 2 450 50 15 34 3 05 46.80 140,393 0.74 11.10 33,300 107,093 2 459 55 M 2 85 43.73 144,302 0.72 11.10 36,630 107,672 2.4 72 60 2.70 41.43 149,131 0.70 11.10 39,960 109,171 2.506 65 15.34 2.60 39.81 _ 155,259 0.69 11.10 43,290 111,969 2.570 70 15.34 2.49 38.17 160,298 0.67 11.10 46,620 113,678 2.610 75 15 34 2.38 36.52 164,351 0.66 11.10 49,950 114,401 22.626 80 15.34 2 27 34.85 167,261 0.65 11.10 53,280 113,931 2.617 85 2 16 3320 169,332 0.64 11.10 56,610 112,722 2 588 90 a 2.06 31.56 170,417 0.64 11.10 59,940 110,477 2.536 95 15.34 1 95 29.91 170,515 0.63 11.10 63,270 107,245 2.462 _ 100 15 34 1 88 28.76 172,586 0.02 11.10 66,600 105,986 2.433 105 15 34 1.80 27.61 173,967 0.62 11.10 69,930 104,037 2.388 110 15.34 1.73 26.46 174,657 061 11.10 73,260 101,397 2.328_ 115 15.34 _ 1.65 25.31 174,657 0.61 11.10 76,593 99,067 2.251_ 120 15 34 1.58 24.16 173,967 0.60 11.10 79,923 94,047 2.159 125 15.34 1.50 23.01 172,586 0.60 11.10 83,250 89,336 2.051 130 15 34 1.46 22.37 174,504 0.59 11.10 86,580 87,924 2.018 135 15.34 142 21.73 176,038 0.59 11.10 89,910 86,128 1.977 140 15.34 1.38 21.09 177,189 0.59 11.10 93,240 83,949 1.927 145 15.34 1.33 20.45 177,956 0.58 11.10 96,570 81,386 1.868 150 15.34 1.29 19.82 178,339 0.58 11.10 99,900 78,439 1.801 155 15.34 19.18 178,339 0.58 11.10 103,230 75,109 1.724 160 15.34 18.69 179,428 0.58 11,10 106,560 72,868 1.673 165 15.34 1.19 18.20 180,226 0.57 11.10 109,890 70,336 1.615 170 15.34 1.16 17.72 180,732 0.57 11.10 113,220 67,512 1.550 175 15.34 1.12 17.23 180,947 0.57 11 10 115,550 64,397 1.478 180 15 34 1.09 16.75 180,870 0.57 11.10 119,880 60,990 1.400 185 15.34 1.06 16.26 150,502 0.57 11.10 123,210 57,292 1.315 Storage Required 2.6263 Outflow Adjustment Factor(m)is(1+Tc/T)/2 (Reference formula 50-6, USD Criteria Manual 2) C w a) C ._ (V N -)--< ryR m O O iri o O U a) a Z:' Z a) a) v \ — a) T.) 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(;((+��++�Y�� Project: Sorrento Subdivision-Sketch Plan -Southeast Project#: Objective: Detention Pond Volume Requirements 1/31/2007 Inflow Data: Design Storm 100 Year Drainage Area 23.65 Acres RiO Coeff(C) O.54 CxA 12.77 Off-Site Flow 0 cfs Time of Concentration ` • 18.8 minutes Outflow Data: Design Storm 1O Year Discharge 21.20 cfs Comment: TIME CxA I Qin VOLin Adjust Ave Clout VOLout VOLtotal VOLtotal (min) (in/hr) (cfs) (cu ft) Factor' (cfs) (cu ft) (cu it) (aO 10 12.77 7.15 91.31 54,788 1.00 21.20 12.720 42,068 0.966 15 12.77 _ 6.10 77.90 70,113 1.00 21.20 19,080 51,033 1.172 20 _ 12.77 5.30 67 69 81,224 0.97 21.20 25,440 55,784 1.281 25 12.77 _ 4.70 60.02 90,036 0 88 21.20 31,800 _ 58,236 1.337 30 12.77 4.25 54.29 97,719 0.81 2120 38,160 59,559 1.367 35 12.77 3.85 49.18 103,275 0.77 21.20 44,520 58,755 1.349 40 12.77 3.55 45.34 108,827 0.74 21.20 50,880 57,947 1.330 45 12.77 3.30 42.15 113,807 0.71 2120 _ 57,240 56,567 1.299 50 12.77 3 05 38.96 116,874 0 69 21.20 63,600 53,274 1 223 55 12.77 2 85 36.40 120,128 0.67 21.20 69,960 50,168 1 152 60 12.77 2.70 34.49 124,148 0.66 21.20 _ 76.320 47,828 1.098 65 12.77 2.60 33.14 129,249 0.64 21.20 82,680 46,569 1 069 70 12.77 2.49 31.77 133,444 0.63 21.20 _ 89,040 44,404 1.019 75 12.77 2.38 30.40 136,818 0.63 2120 95,400 41,418 0951 80 12 77 227 29 01 139,240 0.62 2120. _ 101,760 37,480 0.860 85 12.77 2.16 X27.64 140,964 0.61 21.20 108,120 32,844 0.754 90 12.77 2.0E 26.27 141,868 0.60 21.20 114,480 27,388 0.629 95 12.77 1.95 24.90 141,950 0.60 2120 120.540 21,110 0.485 100 12 77 1.88 23.95 143,674 0.59 21 20 127,200 16,474 0 378 105 1277 1 80 22.99 144,823 0.59 21.20 133,560 11,263 0259 110 12.77 1 73 22.03 145,398 0-59 21.20 139,920 5,478 0.126 115 12.77 1.65 21.07 145,398 0.58 21.20 146,280 (8821 -0.020 120 12.77 1.58 20.11 144,823 0.58 21.20 152,643 (7,817) -C 179 125 12.77 1.50 I 19.16 143,674 0.58 21.20 159,003 (15,325) -0.352 130 12.77 1.46 18.62 145,270 0.57 21.20 _ 165,360 (20,090) -0.461 135 12.77 1 42 18.09 146,547 0.57 21.20 171,720 (25,173) -0.578 140 1277 1 38 17.56 147,505 0.57 21.20 _ 178,080 (30,575) -0.702 145 1277 1.33 17.03 148,144 0.56 21.20 184,440 (36,296) -0.833 150 12.77 1.29 16.50 148,463 ' 0.56 21.20 190,800 (42,337) -0.972 _ 155 12.77 1.25 _ 15.96 148,463 0.56 21.20 _ 197,160 (48,697) -1.118 160 12.77 1.22 15.56 149,370 0.56 21.20 203,520 (54,150) -1.243 _ 165 12.77 1.19 15.15 150,034 0.56 21.20 209,880 (59,846) -1.374 170 1277 1.16 14.75 150,455 0.56 21.20 216,240 (65,785) -1.510 175 12.77 1.12 14.35 150,634 0.55 21.20 222,600 (71,966) -1.652 180 12.77 1•.09 13.94 150,570 0.55 21.20 228,960 (78,390) -1.800 185 12.77 1.06 13.54 150,264 0.55 21.20 235,320 (85,056) -1.953 Storage Required 1.3673 * Outflow Adjustment Factor(m) is (1+Tc/T)/2 (Reference formula SO-6, USD Criteria Manual 2) C 0O N O N V .n . u Er O O O RR\\ X F` V IA \ a) A E Be- LU CO a) m in C C O U o_ N N O a O N N I j p CD C 0 in la N in > co 0 co O O Q V co i.:3- 0 C C o w U m .... 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E ° co c S © \ 3 O / § / + y C - { T. ` ` ro > & D / / z u R \ ] 3 G G j f / \ 5 @ 7 G 3 , 2 \ 2 CC \ / j ) /_ 2 \ ® ` @ ® ca- 4 ° ] y � . > a \ 2 / g z d } 2 k •a n f _ / 2 A u E e - ihi- j 2 z . - -(5 e d _, u 2 § ® 9 w 0 . , > ? / C O O .0 co co C C "- N CC O O 6 U a) r m O N U) •U o_ N 0 S y 5 n) ID up 7 N (o co Q M O N N 0 0 O o _ ,c1- > Y 0 r Q) () O N O > O a) o o -•-• LLI d Q O O i O - N U - r O r O CC O O ≥ o c . � +- z O ° m o a m Y n G) 0 P TO w L a L -p (d h N O O O '_ ° — o O Q �o Q o 0 0 U Cl) o + u •i O m v o j b- o co N L _ O r y w c 0 I a. - c + E E > N (U N < N d O CV) CO O O O co O O I: Q O 6 O Q o] <_ co 6 co o V CO O - O O C + U N N C cc N O O O O + O Q 0 6 ._ 00- co co o N O h ID Ft (13 N O to II co45 U H Q N Ma) p N V (0 t o L UI° O O o a O miii m 2 '- ,o, u) o 0 0 I n 20' I i `I o , Ii 'o N N tTH w a° Ifi . _ O v n a CU I �. , V L. N Ill I a p CO d w _.) .:J IL-�...I i \ CO i ' `tc".' •:I. .11., , \-4 --- .a 't\ , Cr, J i I I ''''\ 5 I I I ' I. V w 1.. .- C. 000 0 0 0 0 0 0 0 _ �, C 0000000000 m —E di.- awnloA 2 "^-.< ` _ c Z o 0 .0 a+ C) n a) o micro R n c > Nw fan 'p N _ X,,H--' - N w V. Q N N ' - V N Ol O 0 0 O W N Q) = � F C a 0 kt V) w w N l0 n E `po °Im0 to o n S N n 0 ' n W O 1n N j N co N E o O T3 1 C to O L > p— Sin _m m 2 w E in Ln Ln to "m •- - o \v worn w N -- o al C ,_ N4 N O N N N ^ V inI.12 Q .- E 5 E crr--- v o R > m N N ltl in to al J(3) N 0 Q o. w 2 C \w N N 0 N $,- N M 4 1n N v N N M O M w a to 61 ?Y tell V w w N r-- L7 6J tYJ 1�. Of N N N O N n O N V P 1`�4: ej m CO OM v ,s3 co '�`IJ Its 4tts — N �— A Q N � M .,4 0 0 0 0 0 0 0 0 0 0 0 0 Q 9 0 Q A 0 0 0 0 0 0 0 CI 0 0 U: u� w in l'a in In kl lLl tO Project: Sorrento Addition -Southwest Detention Basin Project#: ' Objective: Detention Pond Volume Requirements 2/1;2007 Inflow Data: Design Storm 100 Year Drainage Area 108:14 Acres RIO Coeff(C) 0.58 CxA A 62.72 Off-Site Flow 242.9 cfs Includes Off-site + NE 8 SE Del. Basin Discharges Time of Concentration 28 minutes Outflow Data: Design Storm • 5 Year Discharge 32 cfs Comment: Off-Site Flow is Considered as Pass Through TIME CzA I Qin VOLin Adjust Ave Clout VOLout VOLtotal VOLtotal Imin) (in/hr) (cfs) (cu ft) Factor* (cfs) (cu ft) (cu ft) (af) 10 62.72 7.15 448.46 269,074 1.00 32.00 19,200 249,874 5.736 15 62.72 _ 6.10 382.60 344,339 1.00 32.00 28,800 315,539 7.244 20 62.72 5.30 332.42 398,907 1.00 32.00 38,400 360,507 8.276 25 62.72 4.70 294.79 442,184 1.00 32 00 48,000 394,184 9.049 30 62.72 4.25 266.62 479,919 0.97 32.00 57,600 422,319 9 695 35 62.72 3.85 241.53 507,206 0.90 32.00 67,200 440,006 10.101 40 62.72 3.55 222.70 534,475 0.85 32.00 76,800 457,675 10.507 45 62.72 3.30 207.01 558,931 0.81 3200 86,400 472,531 10.848 50 62 72 3.05 191.33 573,993 0.78 32.00 96,000 477,993 10'73 55 62.72 2.85 178.78 589,976 0.75 32.00 105 600 484,376 11.120 60 62 72 2.70 169.37 609,718 0 73 32 00 115,200 494.518 11.353 65 62.72 2 60 - 162.76 634,770 0.72 32.00 124,800 509,970 11.707 70 62.72 2.49 156.04 655,374 0.70 32.00 134,430 520,974 11 •.1 75 62.72 2.38 149.32 671,946 0.69 32.00 144.000 527,946 12121 80 _ 62.72 2.27 14247 683,840 0.68 32.00 153,630 530,240 12173 _ 85 62.72 2.16 135.75 692,308 0.66 32.00 163,200 529,108 12.147 90 62.72 2.06 ' 129.03 696,743 0.66 32.00 172,800 523,943 1212. 95 6272 I 95 122.31 697,146 0.65 32.00 182,400 514,746 11.'17 100 62.72 1 88 117.60 705,614 0.64 32.00 192,000 513,614 11.7.1 105 62.72 180 112.90 711,258 0.63 32.00 201,600 509,658 11.700 110 62.72 1 73 108.19 714,081 0.63 32.00 211.200 502,881 11.545 115 62.72 _ 1.65 103.49 714,081 0.62 32.00 i 220,800 493,281 II.324 120 62.72 1.58 98.79 711,258 0.62 32.00 230,400 480,858 11.039 125 62.72 1.50 94.08 705,614 0.61 32.00 240,000 465,614 10.689 130 62.72 1.46 91.47 713,454 0.61 32.00 249,600 463,854 10.649 135 62.72 1.42 88.86 719,726 0.60 32.00 259,200 460,526 10.572 140 62.72 1.38 86.24 724,430 0.60 32.00 268,800 455,630 10.460 145 62.72 1.33 83.63 727,566 0.60 32.00 278,400 449,166 10.311 150 62.72 1.29 81.01 729,134 0.59 32.00 288,000 441,134 10.127 155 62.72 1.25 78.40 729,134 0.59 32.00 297,600 431,534 9.907 160 62.72 1.22 76.42 733,587 0.59 32.00 307,200 426,387 9.789 165 62.72 1.19 74.43 736,849 0.58 32.00 316,800 420,049 9.643 170 62.72 1.16 72.44 738,918 0.58 32.00 326,400 412,518 9.470 175 62.72 1.12 70.46 739,797 0.58 32.00 336,000 403,797 9.270 180 62.72 1,09 68.47 739,483 0.58 32.00 345,600 393,883 9.042 • 185 62.72 1.06 66.48 737,978 0.58 32.00 355,200 382,778 8.787 Storage Required 12.1726 ' Outflow Adjustment Factor(m)is(1+Tc/T)/2 (Reference formula SO-6, USD Criteria Manual 2) G N C _0 N co N N fr O 6 N � o a) U � , m � M y al th C U o N O O C Oa N_ •- 4 I Do E To' v) c a) in D O o s- N CO O'M 0 c _< _ @ • rr M M U CO in c o m o O )- N u O O N W w a o 0 cD Q p p f° Li- OCD O } U J O w m O 'O w ill o c d O 0 o Q co co a CC o L V O O O -0 N N + U) d o a III O •- co d N a) a o E co a o Q Q o co m m c a o a) + o N w U X a) co co o Co ccoo w - Cs co O CO o °1 or) a Q a I— Q o o c co a 5 U O GO c t V 0 o a) r O o o m c U N o ,E co o a L N ~ c N a o Q O S CC $ '71. \ 2 } ■ „ „ „ ,. „ ., ,. „ „ ., „ ., $ \ / / 3 / / / % / / / § j U) I .. \ ) i- a 2 \ § / m / . a, . , \ -aci (7,--, \ i F-7. \ § Y ~ \ 11.1 o b § ON— az } ) \ Z 9 2� % Q. E R > . 003 - . E C0 o ® � � \ C . _g / \ . . a _ C [ « & § G - RI / j m ' — ' — ` - — n /0 / ± \ C o . § 7 % \ \ s ® J U7 C / / / ID k .ri \ \ m e R 2 0 / o e , / ) .0 •/ ° a / [ CD CI Q , ,_. . . / / \ 4.1 Z: . Ej ) C 4 # @ \ .41 0 < co o © N .1 © c ] iz.- , • \ 0 ( E { \ 3 = a _} § kXZG / c. \ / 0 ® } \ ( \ \ , J \ k ,_ / ® { \ / § a «f $ \ a- $ 0 { { % 2 ; ] 3 . > I- co / / \ Z / ) - k / 2 § ,- \ / CO a ° ~ - \ - m < m 2 ® a • j E4 \ N. CZ- ^ CY O Ai > Z .- Sorrento Addition On-Site Historic based on Developed West Subbasin: 5-year Printouts for User Selected Storm Hydrographs flow in cfs N N C N E ) c o 0 0 0 5 0 10 0 15 0 Z1 20 4 j,/r y rr,o h25 15 30 27 �` ff' g P 3' A5 35 32 , OFY f �lr� 40 32 , Pt 45 29 tv 50 26 L_, hit• 55 23 60 20 65 17 70 15 75 14 80 12 85 10 90 8 95 7 100 6 105 6 110 5 115 5 120 4 125 3 130 3 135 2 140 1 145 1 150 0 155 0 160 0 165 0 170 0 175 0 180 0 c c O G C• C a LL • o¢ ra LL U O C CO j O Au E`rc - N O b _ U- 0 C E o o. y C o o a CO C • C '- C LL y 0 -c O m C O E n C — G L O 0 E2 a a E C N - C O d J N O • O L aa U O C c o v u E y ^ 6 Y a N O W O COC E o v ^ ry i o N c 'E O co • 0 O E o • d O J Q = ea n N W N O N ID 3 m E A � a a o Q' W j rn K W c Q U C W >- c• a w 2 p 7 c c a U E O U O A o a " c N o to d E E L n E U VI 0o O onE — ^ ° C.'i y E E x u ° n o N LL a u w w u o w O Ec o V ° — ne n t A.' E CC Co c m i^ 3 E w 0 ^ v �n o r Qy° a 3 m a c C '76- o 7 3 ^ N E w U 0 cc a � n U o O C a` E a v d N N � p v E p w v A d 3 a � o t b O O 'p O c co 7 E . ° v 5 o z' d o 11 z v 10 E v E E cno w " o` Sorrento Addition 1/30/2007 Historic On-Site Imperviousness Areas WEST Area % Imperviousness (A) (I) A x I Paved 0.72 100 72.05 Roofs/Sidewalks-Driveways 0 90 0 Residential 0.06 43 2.47 Gravel Road 0.24 40 9.60 Turf 107.14 0 0 108.16 84.12 (A x 1)/A 0.78 Value used for CUHP Historic Condition Calculation Culvert Sizing - Off-Site to On-Site at NE Corner of Site - 100-yr Event Worksheet for Circular Channel Project Description Worksheet NE - Corner Culvert Off-to On-Site Flow Element Circular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.013 Slope 0.010000 ft/ft Depth 2.50 ft Diameter 33 in Results / v Discharge 56.57 cfs / it/4/ Flow Area 5.7 ft' J [ •Y Wetted Perimeter 6.95 it £li 1p1 .• f7 1 Top Width 1.58 ft i"f� v4i'r �G1`� Critical Depth 2.44 ft • Y/� tI L{b Percent Full ' 90.9 % ((iF' :i ')l-- • ,/f Critical Slope 0.010206 W t t/ fyi� •Lfv� Velocity 9.98 Ills �L+"� Ji ll1 �Lt` Velocity Head 1.55 ft A,•(" 4 L' Specific Energy 4.05 ft M/n7. Froude Number 0.93 .:7 Maximum Discharge 56.89 cfs ' Discharge Full 52.88 cfs Slope Full 0.011444 fUft Flow Type Subcritical • • Title:Liberty PUD Subdivision,' Project Engineer:Reid W.Bond C\_.\liberty-mead 1-30-07.1m2 Landmark Engineering Ltd FlowMasler v6.116140) 2/1/2007 10.54:05 AM ©Haestad Methods,Inc. 37 Brookside Road Waterbury, CT 06708 USA (203)755-1666 Page 1 Sorrento Addition - East & South Boundary Drainage Ditch (100 Yr. Event) Worksheet for Trapezoidal Channel Project Description Worksheet Drainage Ditch - E&S Boundary (100 Year) Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.030 Slope 0.006000 Wit _O_ 4 r rt Left Side Slope 4.00 H :V :�e d set �o 1,�O Right Side Slope 4.00 HIV •, Qr~f �S fr.) Bottom Width 4.00 ft C� Discharge 233.30 cis .. 1•• cif 5 2 1'?r Results ..EL:x3• Depth 2.87 ft Flow Area 44.4 ft' Wetted Perimeter 27.65 ft Top Width 26,94 ft Critical Depth 2.47 ft Critical Slope 0.012006 ft/ft Velocity 5.26 ft/s Velocity Head 0.43 ft. Specific Energy 3.30 ft Froude Number 0.72 Flow Type Subcritical Title:Liberty PUD Subdivision' Project Engineer: Reid W.Bond f:\...\liberty-mead 1-30-07.fm2 Landmark Engineering Ltd FlowMasler v6.1 (6140] 2/1/2007 10:39:28 AM v Haestad Methods, Inc. 37 Brookside Road Waterbury.CT 06708 USA (203)755-1666 Page 1 Culvert Sizing - Off-Site to On-Site at NW Corner of Site - 100-yr Event Worksheet for Circular Channel Project Description Worksheet West Drain - Offsite to Onsite Flow Element Circular Channel Method Manning's Formula Solve For Discharge Input Data Mannings Coefficient 0.013 Slope 0.010000 fl/ft-': ? ' 2„ Depth 2.00 ft �'�" :.1r4 -per. r : 1 r s5 • Diameter 24 in i , di- Results ,„5 S Discharge 22.62 cis � r" Flow Area 3.1 fP Al Wetted Perimeter 6.28 ft Top Width 5.96e-8 ft Critical Depth 1.69 ft Percent Full 100.0 Critical Slope 0.009461 ft/ft Velocity 7.20 ftis Velocity Head 0.81 ft Specific Energy 2.81 ft Froude Number 1.75e-4 Maximum Discharge 24.33 cfs Discharge Full 22.62 cfs Slope Full 0.010000 ft/ft Flow Type Subcritical Title:Liberty PUD Subdivision'. Project Engineer:Reid W.Bond F.\...\liberty-mead 1-30-07.fm2 Landmark Engineering Ltd FlowMasler v6.116140) 2/1/2007 1O.46:42 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA (203)755-1666 Page 1 BACKGROUND INFORMATION L x p,,,�,,�� yy .' of }*` NSF,�W`-1 r ''Irsk t 5I); ^-44.7, +Tti r n:4 . m c`bC tf 3 W'i ,';'r.% ;'.;4.4.C S^.-tto i 'SM�#•Ji> h1 s �y'S+�Rr C ,,. r, ^.' '".r.yµ' r."�i v t1tI ✓x y, sm ti h4�' X #r n. . . Ia . g t4 �rk i • f -6.1.1",,a! b t t n •,, a 'kr -a0 f3 4 ,, +• y �4' + v fp t -' n .a'r Jr "- G k r s h i .m`Y n4 '^ � r a:, 'tr��"i '`tV;�. vi., F rl, }. ,+.c2-..':::...-_-1<z 1. s 3.p� „ � vat i+-t. .---,-,7-- .n, ,u�> yNffrk�lVA rxt..w 4 a tM tt ,ry't x 'r seo,::.-1.4”.‘t...154," ' ” �T *r^ id R" R 4t 4'ti 4,1t�. h z to z a- -r1,...:4,4-4 '4±z* 4 ., y'^p i�tY R ...? 0ftoli, 'M" "- " . a1Y r�z�yr�� f ' Std ""r +, t .,`� -•Tiii a' f?I t -e'yw y* C 4 44`,/+'•V; �•y ° A'.--1/2a-1?" .r' u`R' .y 4 hNy Rt°et t . N lit,0 tL N";. wgf L kt"roy ' ?I� � 6 n4I` s1'. 2.4..-. .a'" a"ttn 1 t c $1,2.44•4r �y-e Syv z.r M' •h v a ' Y \'�:'" '-ra f. .s„t''�.'ti. •4 ',' •*A -.,;^ x+�r ;4,4••••=i5,!,4"-`��`, °'Si: �'R 5 o[[ �Y Ln Ar l7 F C!'frAIL' (/J / r. e4I E-/> T //pl=c xs4 e. / 7 /�. 1)(414//t1A6t` IQ,re /-% �S �i /1 - n"1'I I ,r,./0 A,/ !4L/ IMF t Rn��0 . ► t/ �. Y RAINFALL DRAINAGE CRITERIA MANUAL (V. 1) • 4.0 INTENSITY-DURATION CURVES FOR RATIONAL METHOD To develop depth-duration curves or intensity-duration curves for the Rational Method of runoff analysis take the 1-hour depth(s) obtained from Figures RA-1 through RA-6 and multiply by the factors in Table RA-4 to determine rainfall depth and rainfall intensity at each duration. The intensity can then be plotted as illustrated in Figure RA-15.6,g (LA•27? TABLE RA-4 Factors for Preparation of Intensity-Duration Curves Duration (minutes) 5 10 15 30 60 Rainfall Depth at Duration (inches) 029P, 0.45P, 0.57P, 0.79P, 1.0P, Intensity (inches per hour) 3.48P, 2.70P, 2.28P, 1.58P, 1.0P, Alternatively, the rainfall intensity for the area within the District can be approximated by the equation: 28.5 P, (RA-3) in which: /= rainfall intensity (inches per hour) Pi = 1-hour point rainfall depth (inches) T = time of concentration (minutes) RA-6 06/2001 Urban Drainage and Flood Control District RAINFALL DRAINAGE CRITERIA MANUAL (V. 1) I 7-- �/T4 ZGL'AF-7--%l,;Li 7A, R 71 W R 70 W R 69 W R 65 W R 67 W R 6ti w R 65 W 0 64 W R 63 W 1.3 1 41.45 1.45 .4 1.35 1. -I/ 1 / 35 1.4 _ 4I \ z L0NGM0NT Of z o 0 Io • Z I� / Lo • I S . OIL Z z z E 1.2I WI?111 DRIGH IC 0 A0A.AS oa \ I m • 00 L.DER 3Er ERSJN ` 311-1 n r ry o: DENVER I (_ ` �`1.1 11.37 X ` 1.39 AHAMS I I U. 'VER _-- ARAPAHO( i \. .- PL • • 1'0 ERG EEN I `v 4.1 APAN0E nnnnm+DE Dl i61A5 ELDON --- 0N1ER 4 • ei (O _ PAU'ER :f0 • _ IC r W EDALIA n X1.39 1.0 1.1 1.2 1.3\ FRANK, V0 1 l 1.4 1.4 R 71 W R 70 W 0 69 W R 611 W 0 67 w 0 66 W 11 65 W 0 64 W 11 63 W FIGURE RA-2 Rainfall Depth-Duration-Frequency: 5-Year, 1-Hour Rainfall i RA-14 06/2001 11 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RAINFALL R 71 W R 70 W R 69 W IL 65 .4 R 67 W R 66 w R 65 w 1161W R El W 1.5 1.6 1.7 1.75 1.75 1 7 1.65 1.6 1.6 1.65 • ,-- \ LONGMONi CI \ t- II MOT , , o � If m 55 - - - i _ I , V: l l -- 1.4 - RR16MI0 nOnl S - n fr- / l J —_ _ Do LIAR �_ _ _1__— JS�_ [F ERSON i e DCNVL'R 1 n I.. v — \ _— I O 'VCR nknP,u lO[ to I in \ N. \ — 1.3 EVE REIN I 1.65 55 r / 5 a / is — __ - J Al nPnr101[ nlinrnnnC CONIFERI in • PARER v v. 0 rc D al D I — a r- --N:_1 N. • 6 0 Lei SEDnllh r r 1.3 1.4 1.5 1 \ I 1.65 1.7 • 1.65 1.7 'I R 71 w R 70 w R 69 W R 68 w R 67 w R 66 W R E5 w R 64 w R 63 W t FIGURE RA-3 .1 Rainfall Depth-Duration-Frequency: 10-Year, 1-Hour Rainfall I J i 06/2001 RA-15 I Urban Drainage and Flood Control District RAINFALL DRAINAGE CRITERIA MANUAL (V. 1) i .,7/ L1PttA r/E/ /17 R 71 W R 70 W I R G9 W R GO W R 67 W ❑ 66 W R 65 W R 64 W R G3 W 2.4 2.5 2.65 2.7 2.7 2.6rr 2 65 2.7 HbTc ± \ I_/ 1 j 1 L J a / WEI. 2 3 - umG11m MS 6 • .DA 14 4 VI o / I co 10 IDER n, J f ER ON I— '1 II r rt1JvpE ! � N 2.2 1 / j Daus — — — D vER AW/Pnn0E o N 2.15 - `\\\ 2.1\ — _ —_ ` — 2.7 I/\UP,,, EEN r-7-tics.in - \ \ / ._-- 2.65 2.05 r _I_ _ a1\NAAS ARAPAn1E D �4US ELUL NI XNIFER , y N m I PoJ. 'ER ,A o ': O o °rc J +m A w / \ 2.05 5CDnua r. 2.6 Ill nNl<A WN \ \ 2.5 \ 2.t 2.IS 22 23 2q 2 ' 5 R 71 W R 70 W It 69 W R 60 W R 67 W R 66 W R 65 W 11 SI W R 63 W FIGURE RA-6 Rainfall Depth-Duration-Frequency: 100-Year, 1-Hour Rainfall RA-18 06/2001 Urban Drainage and Flood Control Dislricl DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF • TABLE RO-3 Recommended Percentage Imperviousness Values Land Use or Percentage Surface Characteristics Imperviousness Business: Commercial areas 95 Neighborhood areas 85 Residential: • Single-family Multi-unit (detached) 60 Multi-unit (attached) 75 Half-acre lot or larger Apartments 80 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 5 Playgrounds 10 Schools 50 Railroad yard areas 15 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off-site flow analysis 45' (when land use not defined) Streets: _. Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 0 Lawns, clayey soil 0 See Figures RO-3 through RO-5 for percentage imperviousness. Based in part on the data collected by the District since 1969, an empirical relationship between C and the percentage imperviousness for various storm return periods was developed. Thus, values for C can be determined using the following equations (Urbonas, Guo and Tucker 1990). CA = K,, + (1.3 li' - 1.44/2 + 1.1351— 0.12) for CA ≥ 0, otherwise CA = 0 (RO-6) CcO = K . + 0.858/3 - 0.786i' + 0.774i+ 0.04) (RO-7) Ca = (CA + Ca,)/2 in which: • I = % imperviousness/100 expressed as a decimal (see Table RO-3) 06/2001 RO-9 Urban Drainage and Flood Control District RUNOFF DRAINAGE CRITERIA MANUAL (V. 1) C, = Runoff coefficient for Natural Resources Conservation Service (NRCS) Type A soils CB = Runoff coefficient for NRCS Type B soils CCD = Runoff coefficient for NRCS Type C and D soils KA = Correction factor for Type A soils defined in Table RO-4 Ka) = Correction factor for Type C and D soils defined in Table RO-4 TABLE RO-4 Correction Factors K,, and Km for Use With Equations RO-6 and RO-7 Storm Return Period NRCS Soil Type 2-Year 5-Year 10-Year 25-Year 50-Year 100-Year C and D 0 -0.10/ + 0.11 -0.181+0.21 -0.281+ 0.33 -0.33;+ 0.40 -0,39: + 0.46 A 0 -0.081+ 0.09 -0.14/+ 0.17 -0.19i + 0.24 -0.22;+ 0.28 -0.251 + 0.32 The values for various catchment imperviousnesses and storm return periods are presented graphically in Figures RO-6 through RO-8, and are tabulated in Table RO-5. These coefficients were developed for the Denver region to work in conjunction with the time of concentration recommendations in Section 2.4. Use • !+ of these coefficients and this procedure outside of the semi-arid climate found in the Denver region may not be valid. See Examples 7.1 and 7.2 that illustrate the Rational method. The use of the Rational method in storm sewer design is illustrated in Example 6.13 of the STREETS/INLETS/STORM SEWERS chapter. • RO-10 06/2001 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 1) RUNOFF 90 -- 80 • - -15.000 s0.It hones I-I70 --, / ' 4,000 sq.It.homes 60 r I.' - /� - (3.000 s0.ft.homes I Z a 50 - n I , - - r%j/ f ' • I2.000 se.R.Iwmes I . /d0 / / �' /•' / tOCA sq.K.hones 20 - 10 0 0 1 2 3 d 5 6 Single Family Dwelling Units per Acre FIGURE RO-5 . Watershed Imperviousness, Single-Family Residential Two-Story Houses 100 0 90 0 80 _. / 060 y .S I // �c —f 50 Yr 050 J / /�I a50 Yr a l ./�� ti.—10-yr a _ 1 /' .--.-5-yr i 060 •-,,,j---1.-----:_ ,A w-2.yr D 30 010 ' 000 �___.__.___.___________ 0% 10% 20% 30% 40% 50% 60% 70% 60% 90% 100% Watershed Percentage Imperviousness FIGURE RO-6 Runoff Coefficient, C, vs. Watershed Percentage Imperviousness NRCS Hydrologic Soil Group A 06/2001 RO-17 Urban Drainage and Flood Control District Statement ofSchool"Impact Sorrento EstatesAnne. ation It is anticipated that the St. Vrain School District will provide a current referral letter as part of their review of the Sorrento Estates Annexation however; the District has previously reviewed the development through a Weld County referral process. That referral letter dated September 6, 2005 is attached. The District reviewed the development proposal in the form of(1) available school capacity (2) required land dedications and/or cash-in-lieu fees and (3) transportation considerations. A summary of the comments follow: • Of the schools in this feeder, Mead Elementary School is expected to exceed the 125% of its capacity within the next 5 years. Mead Middle school, at a projected capacity of 121%, is also fast approaching the capacity benchmark. • Should a plat application related to this application be submitted in the near future, School District would not support that application due to capacity concerns within this feeder. • Currently, additional capacity for this feeder under the 2002 Bond is provided at the high school level only. However, no construction date has yet been established for this high school facility and Skyline High School may experience short-term crowding in the interim. Detailed information on specific capacity issues, the cash-in-lieu/land dedication requirements and transportation impacts for this proposal follow in the attached letter mentioned above. The recommendation of the District noted above applies to the attendance boundaries current as September 6, 2005. The attendance boundaries may change in the future as new facilities are constructed and opened. The implementation of the Intergovernmental Agreement (IGA) Concerning Fair Contributions for Public School Sites requires that the applicant either dedicated land directly to the School District or pay cash-in-lieu (CIA) based on the student yield of the development. The Sorrento Estates Annexation will provide the necessary cash-in-lieu to the St. Vrain Valley School District based on the current requirements at the time of final platting. That fee is anticipated to be $645.00 per dwelling unit. Understanding the District's concern for school capacities and enrollment projections, the developer of Sorrento Estates intends to participate in the Voluntary Capital Mitigation Fee. The policy indicates that methods of staging the voluntary contribution can be reviewed on a case by case basis. The developer will being negotiations with the school district to discuss the staging methods, mitigation fee, and separate agreement upon annexation of the property. OCT-13-2005 THU 08: 52 AM SOUTHWEST WELD PLANNING FAX NO. 720 652 4211 P. 21 St.�iam Vaiey School District Weld County Planning Department GREELEY OFFICE September 6, 2005 SEP 8 2005 Jacqueline Hatch Weld County Planning Department ED RECEIV 918 10th St. RECEIVED M G 8.� Longmont, CO 80631 RE: Liberty Properties LLLP Planned Unit Development Sketch Plan (Situate in the NW 74 of Section 32, T3N, R68W) Dear Jacqueline: Thank you for referring the Liberty Properties LLLP Planned Unit Development Sketch Plan to the School District. The District has reviewed the development proposal in terms of (1) available school capacity, (2) required land dedications and/or cash-in-lieu fees and (3) transportation considerations. After reviewing the above proposal, the School District has listed comments on this page and Attachment A. A summary of these comments is as follows: • Of the schools in this feeder, Mead Elementary School is expected to exceed the 125% of its capacity within the next 5 years. Mead Middle school, at a projected capacity of 121%, is also fast approaching the capacity benchmark. • Should a plat application related to this application be submitted in the near future. School District would most likely not support that application duo to capacity concerns within this feeder. t--- • Currently, additional capacity for this feeder under the 2002 Bond is provided at the high school level only. However, no construction date has yet been established for this high school facility and Skyline High School may experience short-term crowding In the iterim. Should this development be approved, the options for managing the short and long term overcrowding in these schools may include adding modular classrooms and implementing split or staggered schedules as.needed. Other options may include, but not be limited to, implementing year-round schools or asking voters to approve new bonds for additional school facilities or a mill levy for additional operating funds. It should be noted that a lack of operating funds may be a factor in delaying construction and occupancy of new school facilities in this area. Detailed information on the specific capacity issues, the cash-in-lieu/land dedication requirements and transportation impacts for this proposal follow in Attachment A. The recommendation of the District noted above applies to the attendance boundaries current as of the date of this letter. These attendance boundaries may change in the future as the new facilities are constructed and opened. If you have any further questions or concerns regarding this referral, please feel free to contact me via a-mall at secirue glen@stvrain.k12.co_us or at the number below. Sincerely, Glen Segrue AICP Planning Specialist Enc: Exhibit A - Specific Project Analysis ST.VRAIN VALLEY SCHOOL DISTRICT PLANNING DEPARTMENT.395 SOUTH PRATT PARKWAY,LONGMONT,CO 80501,SCOTT TOILLION,DIRECTOR.PHONE 303.682-7229. FAX 303.682-7344. OCT-13-2005 THU 08:53 AM SOUTHWEST WELD PLANNING FAX NO. 720 652 4211 P. 22 ATTACHMj ft-Saecltic Protect Analysis PROJECT: Liberty Properties LLLP Planned Unit Development Sketch Plan • In SCHOOL CAPACITY The Board of Education has established a District-wide policy of reviewing new development projects in terms of the impact on existing and approved school facilities within the applicable feeder system. Any residential project within the applicable feeder that causes the 125% school benchmark capacity to be exceeded within 5 years would not be supported. This determination includes both existing facilities and planned facilities from a voter-approved bond. The building capacity, Including existing and new facilities, along with the impact of this proposal and all other approved development projects for this feeder is noted in the chart below. CAPACITY INFORMATION CAPACITY.BPNCHMARK • • , Uncluita pretreated&uQenls,plus oevelopmenra elueont impact) School Dullding Sties. Sidi. '2005-2006 2oo6:2p07 2007-2006 .2008-2009 2009.201@ Level Capacity Oct-04 Impact Stdt5- . Cap,r. Stdta Cap. Stdts Cay_ 5ldts Cap. Sidle bap. Elementary 504 451 65 459. 91% . 574'. 114% 696.' 118% 622 123% 646 126% Middle 360 531 26 360 '. 100% 367 .10290 376 104% 414 115% 436' 121'% High School' 2073 1446 32 146@ .' 71% 1576 76% 1636 79% 1708 — 82% 1770 ••85/ Total 4272 123 2288 .2517 2600 274-4 •2852 *combines capacities of existing schools and those approved In the 2002 bond that WO alleviate this lender Specific comments concerning this proposal regarding School Capacity are as follows: • Specific Impact - This application will add 186 new single-family dwelling units and will impact Mead Elementary, Mead Middle and Skyline High School • Benchmark Determination — Of the schools in this feeder, Mead Elementary is projected to exceed the 125% capacity benchmark at this time with the addition of students frorn this development. • Additional Capacity Impacts—The 2002 Bond did includo an additional high school in this feeder, which is included in the capacity calculations above. However, there may be short-term capacity shortfalls at Skyline High School until this facility is constructed. Additional middle and elementary school capacity will most likely become available only after the approval of a now facility bond in the future. • Phasing - The District would appreciate a phasing plan from the developer to better determine enrollment and capacity impacts on the affected schools. (21 LAND DEDICATIONS AND CASH IN-LIEU FFFS The implementation of the Intergovernmental Agreement (IGA) Concerning Fair Contributions for Public School Sites by Weld County requires that the applicant either dedicate land directly to the School District along with provision of the adjacent Infrastructure and/or pay cash-In-lieu (CIL) fees based on the student yield of the development. CIL fees only provide funds for land acquisition, which is only a small component of providing additional school capacity for a feeder. Specific comments regarding land dedications and CIL fees for this referral are as follows: • Dedication and/or Cash-in-lieu Requirements — According to the District's Comprehensive Facility Plan, there is a need for a school site in this general area. The School District would welcome discussions with the applicant about a possible elementary school dedication at this location. • Number of Units covered by dedication/cash-in-lieu — An elementary site dedication (10 acres) would excuse this development from paying CIL fees for all 186 units. Otherwise, fees would be assessed per the attached chart. • Dedication/Cash-in-lieu Procedures- Cash-in-lieu payments are to be made to the St. Vrain Valley School District Business Office—395 S. Pratt Parkway, Longmont, CO. 31 TRANSPORTATION/ACCE53. Transportation considerations for a project deal with busing and pedestrian access to and from the subdivision. Pedestrian access, in particular, is an Important goal of the School District in order to facilitate community connection to schools and to minimize transportation costs. Specific comments for this application are as follows: • Provision of Busing- Busing for this project, under the current boundaries, would most likely be provided. • Pedestrian and Access Issues— Internal pedestrian access is adequate within this development as are the connections to potential future developments In the area. The District is particularly encouraged by the pedestrian underpass through the 1.25 parallel arterial. ST.VRAIN VALLEY SCHOOL DISTRICT PLANNING DEPARTMENT.395 SOUTH PRATT PARKWAY. LONGMONT,CO 80501.SCOTT TOILLION,DIRECTOR.PHONE 303-682-7229. FAX 303-682-7344. OCT-13-2005 THU 08:53 AN SOUTHWEST WELD PLANNING FA;{ NO. 720 652 4211 P. 23 ca c aa- = u � 3 - E N1741 Q a CI b0 C G C ri . 0 .2 A. C O <J % 5 O O S ' . I_--Io0 4 U I LI U '4 Na .1 . M c c 4 �q a, a. �QQ L] o U H -1 .�tn 12 1 15 1 17 8 Iii 8 1 8 C :l aaYY > � �r1 "� v'f �n � �n � '> M M a V1 t1 --,-...ti V M CIO 0 v► �� y v► y eA h "4 le. 44.4 r .t:, Ci 'Cf :7 e w N . � N ko a, i • in O V 10 L S y O a, ti C�` Ni ts,�3 O O £ C �l ^�` -- � - a G � Z ti .3 ! `i -a v F �O 0 � Ii ti O Ii 4; i z =I `� , 41 2 c.l� Ewa u, { 1•! RI ______k___-- tol .—►— a. - t i �tn ai ` to cal O ►.fl 1 93 = p a, p N 0 .p `� 5 y a1 _ to — L. `0 L n o N. U 1 `g . 4! U g O g O M N *O �,It. �_ LtJ b W w° �u tr 'v 1 an rt 4. g .J v rev N u. ar s I O ta ro o v I m f I x I— in 4, L1 Csi Impact Assessment Sorrento Estates Annexation Assessment of the proposed annexation as it relates to various infrastructure, utilities and service providers. Water The site is located in the Little Thompson Water District's(LTWD) service area. LTWD will be providing potable water for the site. In working with LTWD's Engineer, Michael Cook, the developer has paid LTWD to have a water system hydraulic analysis performed to confirm that sufficient water quantities and pressures are available to serve this subdivision. The analysis has been completed and LTWD has provided a signed Main Line Water Extension Agreement confirming their ability to serve the site along with a Commitment to Serve letter for up to 186 residential lots and 5.2 acres of commercial development(community recreation center). Northern Colorado Water Conservancy District has a 28-inch raw water transmission line located approximately 75 feet south of County Road 32. The developer of Sorrento Estates Annexation is contributing to a proportional share agreement with the developer of Range View Estates for design and construction of a Little Thompson Water District 12 inch water main extension from Single Tree Estates west to the Sorrento Estates Annexation along Adams Avenue. An existing 6-inch water main is located in County Road 32 (Adams Avenue) and most of it will be abandoned after the 12-inch proposed water main is installed. A portion of the 6-inch main on the north edge of the Sorrento Estates Annexation will remain in service and will be interconnected with the 8-inch waterman that will extend through the Sorrento Estates Annexation. Water mains in the Sorrento Estates Annexation will all be 8-inch PVC pipe and will be looped as required by the Little Thompson Water District. The majority of the water mains will be within the Town of Mead's 60' public right of way. Exceptions will occur where mains will be run in some utility easements to achieve a looped water system. Sewer Sewer service will be provided by the St. Vrain Sanitation District. A petition for Inclusion fee has been paid to the St. Vrain Sanitation District and a Court Order of Inclusion has been approved by the Weld County District Court for the inclusion of the Sorrento Estates Annexation PUD into the St. Vrain Sanitation District. The Sorrento Estates Annexation developer has financed the design and proposed installation of a 15 inch sewer main to be extended from south of Highway 66 north to the southwest corner of the Sorrento Estates Annexation development. Funding for the construction has been contributed to the St. Vrain Sanitation District and construction should begin in the spring of 07. Sanitary sewer within the Sorrento Estates Annexation property will be provided by an 8 inch sewer main. The sanitary sewer mains through the development are proposed to be within the Town of Mead's 60' public roadway right-of-way. Natural Gas Xcel Energy has an existing gas lines in and adjacent to County Road 32. Preliminary discussion with Xcel Engineers indicates that an extension from Weld County Road 7 to the Sorrento Estates Annexation may be required. Electric United Power has existing lines in and adjacent to County Road 32 and can provide the necessary service to the Sorrento Estates Annexation. Telephone An underground telephone line is located on the south side of County Road 32 and the phone company will be capable of providing service to the Sorrento Estates Annexation. Streets Access is critical to the Sorrento Estates Annexation PUD as it requires consideration of the hierarchy of existing and future roadway systems including local, collector and arterial roadways adjacent to and within the site to ensure adequate access and safe vehicular, bicycle, and pedestrian movement. Site Access and Intersection Improvements The Sorrento development will be served by a single full movement access on WCR 5 and two full movement access points on Adams Avenue (WCR 32). Improvements for the site access, WCR 5 and Adams Avenue and Highway 66 and WCR 5 are as follows with their required lengths. • WCR 5/Site Access- an exclusive northbound right-turn deceleration lane with a length of 220 feet which includes a 120- foot taper length; • WCR 5/WCR 32- an exclusive northbound right-turn deceleration lane with a length of 210 feet which includes a 120-foot taper length; • SH 66/WCR 5- an exclusive westbound right-turn deceleration lane with a length of 700 feet which includes a 300-foot taper length and an exclusive eastbound left-turn lane with a length of 965 feet which includes a 300-foot taper length. There is an existing eastbound left-turn lane which may be sufficient to accommodate the short term traffic until SH 66 is widened to four lanes. Sorrento development shall only be responsible for its proportionate share of the cost of construction for a traffic signal at SH 66/WCR 5 intersection. County Road 32 (Adams Avenue) County Road 32, located on the north boundary of the property is an unimproved two-lane, east- west gravel road with 60' existing right-of-way (ROW). County Road 32 is designated as a minor arterial road and will require an additional right of way dedication and paving with this project. The additional 20' ROW shall be dedicated by the Sorrento Estates Annexation plat to provide the 50' 1/2 ROW right of way required for the 100' ultimate right of way. The proposed roadway shall include a 24' asphalt road with 4' asphalt shoulders. The Sorrento Estates Annexation PUD shall gain access from two access points along Adams Avenue. County Road 5 (I-25 Parallel Arterial) County Road 5 is an existing paved two-lane, north-south, 24' road within a 60' right of way (ROW) located along the west boundary of the property. County Road 5 has been designated as the Future 1-25 Parallel Arterial Road. The future arterial designation requires that the developer dedicate an additional 40' of ROW so that a 70' 1/2 ROW can be achieved along the east side of County Road 5. It is expected, based on our existing traffic analysis, that improvements to County Road 5 should be limited to right-in and right-out acceleration and deceleration lanes and a north bound right turn lane at County Road 32 (Adams Avenue). No other improvements are intended. The Sorrento Estates Annexation PUD shall gain access from a single full movement access point on County Road 5. Interior Roadway and circulation This estate lot development will gain vehicular access from Weld County Road 5 at one location and Weld County Road 32 (Adams Avenue) at two locations. The internal roadway network within the estate lot development shall consist of a main looped local collector road with a series of cul-de-sacs and local streets. All internal roadways within the estate lot development shall have a 60' public right-of-way with a 44' paved roadway, curb and gutter, 7' tree lawn, and a 5' detached walk. Drainage A complete Preliminary Drainage Study has been included with the Annexation submittal package. Law enforcement Police protection shall be provided by the Weld County Sheriff's Office. As requested by the sheriffs office an area for school bus loading and unloading has been identified. In addition, a shelter for school children has been provided. Fire protection Fire and Rescue shall be provided by Mountain View Fire Protection. A water system hydraulic analysis has been performed and confirms that sufficient water quantities and pressures are available to meet required fire flows. Roadways have been designed to support fire apparatus and include paved roadway widths of 44' from flow line to flow line with in 60' right of ways. Fire hydrant placement has been provided based on a minimum off a minimum 300' radius. Parks & Recreation Park/open space within the development accounts for approximately 25% of the total development area. Included in the park space requirements is a proposed community recreation center. MI common open space will be owned and maintained by the Homeowners Association. Approximately 37.51 acres of park and open space will be dedicated with Sorrento Estates development within parks and play areas (11.68 ac), buffer yards (4.56 ac), greenbelts (14.81 ac) and a 40,000 square foot recreation center (6.45 ac). The size and location of parks, open play areas and greenbelts provide pedestrian access for children; encouraging safe walking and bicycling routes with minimized street crossings. Developed Park Land The neighborhood recreation center has been centrally located in order to provide easy access to and from neighborhoods. The recreation center is intended to be a meeting place for the development to encourage interaction with neighbors. The recreation center is primarily intended for the Sorrento PUD residents however, will also be available to the public through membership. The 40,000 square foot recreation center building may house community offices, restaurant and health club, a gathering space, mini-library, game room, and media room. Additionally, a community pool, tot lot play area, play fields, barbeque pits and picnic areas will be located adjacent to the recreation center building. The 40,000 square foot recreation center building may house community offices, restaurant and health club, a gathering space, mini-library, game room, and media room. Additionally, a community pool, tot lot play area, play fields, barbeque pits and picnic areas will be located adjacent to the building. In addition to economic feasibility needed to make construction of the recreation center viable, the Sorrento community will need to be effectively established and able to support and maintain a recreation center with so many amenities. Issuance of the 100th building permit is anticipated to trigger the construction of the recreation center. It is anticipated that the sales from 100 lots within the Sorrento development will allow the developer to gain the necessary capital to build the recreation center and associated infrastructure. Undeveloped Park Land Sorrento Estates boasts a unique site design of estate size lots complemented by 30+ acres of spacious greenbelts and buffer yards. Every lot within the Sorrento Estates development backs to open space. Undeveloped park/open space will be landscaped with regionally appropriate plant materials (a "naturalistic" design approach shall be used) in open space and buffer yard areas. These areas shall include informal plantings of coniferous and deciduous trees with large drifts of deciduous and coniferous shrub beds. Turf areas will incorporate low water use drought tolerant seed and sod varieties. Common open space areas as shown on the plans including entry features and landscaping shall be planted and irrigated by the developer and maintained by a common Homeowners Association. The landscape planting and maintenance shall provide a consistent landscape between lots and open space throughout the development. A landscaped buffer yard shall buffer County Road 5 and County Road 32 along the perimeter of the development. The 70' wide buffer yard will enhance the privacy of the residents while providing an attractive edge from the public view. Perimeter fencing shall include 3-1/2' high wood rail fence with masonry columns with sandstone veneer to complement the project entry signage. A tree lined streetscape has been designed for the Sorrento Estates Annexation PUD subdivision along all internal the local roads throughout the development. Street trees planting will have approximately 50± spacing within 7' wide tree lawns shall planted an irrigated by the developer and maintained by the Homeowner's Association. Irrigation The developer, Liberty Properties LLLP, owns four (4) shares of Highland Ditch Company and six (6) shares of the Lake McIntosh Reservoir Company. This water will be used to irrigate the open space throughout the Sorrento Estates Annexation development. Research and discussion with the appropriate ditch company representatives will be conducted by Aqua Engineering to verify data regarding water quantity, seniority, water delivering and timing in sufficient detail to design irrigation pond and to understand water availability. Front, side and rear yard landscaping and permanent underground irrigation shall be installed on each lot by the home owner from back of walk to foundation and maintenance of the private lot landscaping shall be the responsibility of the homeowner. All common open space shall be irrigated with irrigation ditch water conveyed to an onsite irrigation pond located in the southwest corner of the site and then pumped into an automated underground irrigation system. The developer proposes to install a non-potable irrigation system that will be used to irrigate the common open space areas and tree lawns adjacent to street rights of way. The combined detention/irrigation holding pond will have the maintained high water elevation for irrigation purposes with detention volume water occurring above this elevation. The irrigation pond will be lined with an impervious liner and irrigation water will be conveyed from the Highland Ditch Company south along County Road 5 to the irrigation pond. The developer shall transfer adequate shares of the Highland Ditch Company water to the Homeowners Association for ongoing irrigation use. An irrigation pump house is proposed at the southeast corner of the subdivision near the irrigation pond. The pump house will have filtration and pumping equipment to supply pressurized water to the underground irrigation distribution system. The non-potable irrigation system will be transferred to the subdivision's Homeowner's Association who will be responsible for operating and maintaining the entire irrigation system. Because irrigation ditch water is normally available during the months of May through early September, a need for irrigation water exists in the early season (before May) and late season (September and October). A back-up potable water source from the Little Thompson Water District will be installed. However, this potable source will only be used to irrigate selected areas of the site and not the entire irrigated area. The areas to be irrigated with potable water would include the club house, athletic fields and high visibility areas like the main entrance. Environmental consideration There are no environmentally sensitive areas or wetlands as defined by the US Army Corps of Engineers located on the site. No development of land is possible without impacts to the environment. These impacts are mitigated site wide by utilizing proper engineering, planning, and construction techniques. The park land and open space dedicated to buffer yards, greenbelts and landscaping mitigate the negative impacts of noise, vibration, smoke, dust, odors, heat, light and glare. These open areas are strategically located to respect views and mitigate any negative visual and aesthetic impacts of development. As a residential development, electrical interference is not an anticipated environmental impact of this development. Water pollution impacts are largely mitigated by engineering solutions such as landscaped drainage ways, erosion control elements such as erosion fences and baffles, and the storm water detention/irrigation pond. (See the engineering plans and reports for additional details.) The sewage/wastewater disposal facility is St. Vrain Sanitation District. The project is not expected to have significant impacts to rare plant species or wetland areas as neither currently exist on the site. The site is currently an agricultural use. As such there is no removal of natural vegetation. Erosion and sedimentation impacts are mitigated through engineering solutions such as erosion fences and baffles. All construction activities (i.e. excavating, filling and grading on the site shall conform to the standards set forth in the Mead Code and Design Standards, and those by the State of Colorado. These standards ensure that development impacts of this type are limited and acceptable. Drilling, ditching and dredging are not a component of the plan. All new residential development meeting the needs of a growing population will impact the existing air quality to some degree. The low density of 1.08 dwelling units per acre, buffer yards and greenbelts all aid in the mitigation of the impacts of air pollution in this residential development. It is anticipated that recycling and solid waste removal will be managed by a single service as designated by the homeowners association. While the impacts of solid waste cannot be fully mitigated, a single provider will minimize traffic, pollution, and roadway wear and tear impacts over having multiple providers. The project is not expected to have significant impacts to rare wildlife species as none have been identified on the site. Wildlife species that are sensitive to human disturbance will be replaced with more urban adapted birds (American Robin, house sparrow, house fmch, starling, etc), mammals and reptiles. Crown cover of trees and shrubs will provide habitat for urban adapted species. Economic Development Potential The Sorrento Estates Annexation takes a step toward creating a community that meets the needs of Mead's diverse population by complementing the existing housing market with a low density residential estate lot development and community recreation center. Sorrento Estates Annexation will be unique due to its proximity to the intense development occurring in the surrounding area and adjacency to the future I-25 parallel arterial (County Road 5) and close proximity to Highway 66 Corridor. This location offers an opportunity to create a neighborhood that encourages connectivity, protects view corridors to the West, provides open space and recreational amenities, and will provide quality residential housing that will create a neighborhood worth coming home to. The development contains single family estate lots complemented by a neighborhood recreation center designed to invite neighbors to share in the community experience and encourage active lifestyles. The Sorrento Estates Annexation will offer a $3.8 million dollar fiscal benefit to the Town of Mead from revenues (one-time and reoccurring) including but not limited to: property tax, building permits, transportation, open space, police protection, municipal facilities, park system, - recreation center, downtown revitalization, capital equipment, street maintenance, storm water and drainage. Compatifility Assessment Sorrento EEstatesAnnezalion The following is an assessment of the Sorrento Estates Annexation as it relates to the Town of Mead Comprehensive Plan, Land Use Code, and plans and policies for subdivision design and transportation. The Soncuto Estates Annexation property is located at the southeast corner of Weld County Road 5 and Weld County Road 32, southwest of Mead, Colorado. The site is located with the Town of Mead's Area of Influence. The property to the north of Sorrento Estates Annexation is currently vacant property within the Town of Mead Area of Influence and is identified on the Land Use Plan as appropriate for low-density residential development. The property to the northeast, Range View Estates is a proposed development currently under design and review. The property directly east of the Sorrento Estates Annexation is a Weld County development, Eden's Reserve. The property to the south is vacant farmland also within the Town of Mead Area of Influence also identified as appropriate for low density residential development The Town of Mead Comprehensive Plan (MCP) and Land Use Plan identify the area as Low Density residential with a density range of 0.5-1.0 dwelling units per acre. The MCP notes that the term "density" in the CMP for development is in its "gross density" sense. The MCP recognizes that development should be evaluated based on the acceptable number of dwelling units which appear to be consistent with the land use designations identified in the MCP and do not account for areas such as wetlands,road rights-of-way or stormwater detention facilities. Sorrento Estates Annexation-158+/- Ac Low-Density Residential Development REQUIRED PER PROPOSED TOWN OF MEAD SORRENTO ESTATES GROSS DENSITY 0.5-1.0 DU/AC 1.10 DU/AC LOT SIZE 7,000 SQUARE FEET 23,408 (AVERAGE) FRONT YARD SETBACK 20' 30' SIDE YARD SETBACK 5' 10' REAR YARD SETBACK 30' 30' FROM PRINCIPLE ACCESSORY STRUCTURE 5' STRUCTURE PROPOSED OPEN 0.08 AC PER DU 0.21 AC PER DU SPACE/PARK SPACE 14 ACRES 37.51 AC ROAD RIGHT OF WAY 54' 60' ROADWAY WIDTH 36' 44' SIDEWALK WIDTH 4' RESIDENTIAL STREETS 5' INTERIOR 5' COLLECTOR STREETS 8' PERIMETER The 158± acre Sorrento Estates Annexation is low density residential development with 175 estate lots for custom and semi-custom residential housing. The estate lot development will be complemented by 37+acres of park and open space including a community recreation center that has been centrally located in order to provide easy access to and from neighborhoods. The+158 acre site development area of the Sorrento Estates Annexation has a gross density of 1.10 Dwelling Units per acre and includes: • 94.04 acres of low density estate residential use; • 23.15 acres of interior road right of way;and, • 37.51 acres of open space/park land The minimum lot size for residential design identified in Section 16-8-40 identifies a minimum lot area of 7,000 square feet. The average lot size within the Sorrento Estates is 23,408 sq. feet. The large lots will be complemented by 30' font and rear setbacks and 10' side yard setbacks. The current standards call for a 20' front yard setback, 5' side yard setback and 30' rear yard setback. All arrrssory structures will be designed with an allowed setback from the principal structure rather than a property line to encourage openness. Park/open space within the Sorrento development accounts for approximately 25% of the total development area greatly exceeding the 0.08 acres per dwelling unit(14 acres) of park and open space. Sorrento Estates will dedicate approximately 37.51 acres to park and open space as follows: • parks and play areas(11.68 ac), • perimeter buffer yards(4.56 ac), • greenbelts(14.81 ac)and; • 40,000 square foot recreation center(6.45 ac) The Sorrento property is bound on the north by County Road 32 (Adams Avenue) classified as a minor arterial requiring 100' of right of way. County Road 5 on the west is the future I-25 Parallel Arterial alignment identified in the Mead Transportation Plan; requiring 140' of right of way. The Sorrento Estates Annexation will provide the necessary half right-of-way requirements for both arterial roadways and will make the infrastructure improvements necessary to mitigate the impacts of the Sorrento development. The Town of Mead design criteria for roadway design includes a 54' public right of way with a minimum 36' roadway and 4' sidewalks in residential areas and 5' sidewalks along collector streets. Site design and development standards within Sorrento Estates include an interior roadway design that is greater than the Town of Mead residential street standards to maintain an open feeling throughout the neighborhood and improve neighborhood driving conditions. All interior roadways shall have a 60'public right-of-way with a 44' paved roadway, curb and gutter, 7' tree lawn, and a 5' detached walk. The roadway widths are wider than the Town of Meads standards however, the developer feels that the extra costs in designing and installing wider roads will be outweighed because the wider roads will create safer driving conditions (spring and summer pedestrian traffic/winter snow removal) and maintain a sense of openness throughout the development. It is anticipated that large vehicles and recreational vehicles will be typical for this neighborhood and the wider roads will create more desirable driving conditions with better view of pedestrian and vehicular traffic. LARGE MAPS AVAILABLE FOR VIEWING AT THE CLERK TO THE BOARD'S OFFICE, IN THE PUBLIC REVIEW FILE. . . .. ___.. .__ Town of Mead P.O.Box 626 441 Third Street Mead"A Link Tmw Mead,Colorado 80542-0626 With a Big Future" (970)535-4477 CERTIFIED MAIL # 7006 2150 0002 8658 6206 May 10, 2007 Weld County Board of Commissioners P.O. Box 758 Greeley, CO 80632 RE: Required Annexation Impact Report - Sorrento Estates Annexation to the Town of Mead. Gentlemen: In accordance with the requirements of C.R.S. § 31-12-108.5, enclosed is a copy of the Annexation Impact Report prepared for the proposed Sorrento Estates Annexation to the Town of Mead. You have received prior notice of the public hearings before the Planning Commission and the Board of Trustees for this proposal. In the event that you have any questions regarding this Annexation Impact Report, or the proposed annexation, you may contact Richard E. Samson, the Town's Attorney, at(303) 776-1169. Very truly yours, - *at&L- Candace Bridgwater Town Clerk n r rn " 3rTrt C) 3 0 m — cn rn D cis rn—i N < cc : ( MI soipL Annexation Impact Report Sorrento Addition NAME OF ANNEXATION: Sorrento Addition The purpose of this report is to satisfy the requirements of CRS 31-12-108.5 which indicates that a municipality shall prepare an Annexation Impact Report and file a copy of the report with the Board of County Commissioners governing the area proposed to be annexed. Attached to this report are the following: • A map showing the present and proposed boundaries of the Town of Mead in the vicinity of proposed annexation. A Vicinity Map is attached. • Impact Report Map — Showing the present streets, major trunk water mains, sewer interceptors and outfalls, other utility lines and ditches, and the proposed extension of such streets and utility lines in the vicinity of the proposed annexation; and • Impact Report Map — Showing the existing and proposed land use pattern in the area to be annexed; a. The area of the proposed annexation is presently being used for cultivated agriculture. The petitioner of the annexation intends to develop the property for low density residential use in accordance with the Town of Mead Comprehensive Plan and proposed PUD zoning. See Concept Plan. b. Attached to this report is a copy of a pre-annexation agreement between the petition and the Town of Mead. A pre-annexation agreement is not anticipated for this project. c. The Town of Mead, Little Thompson Water District and St. Vrain Sanitation District service providers plan to extend services into the area of the above referenced annexation. The developer will be responsible for the cost of extending streets and utilities to serve the development. The required transportation infrastructure improvements for Adams Avenue (Weld County Road 32) will be extended from the southwest corner of the proposed Range View development to Weld County Road 5. At this time, the Range View Plat is currently in design. The developer of Sorrento Addition is contributing to a proportional share agreement with the developer of Range View Estates for design and construction of the Little Thompson Water District's 12 inch water main extension from Single Tree Estates west to the Sorrento Addition. The Sorrento Addition developer has financed the design and proposed installation of a 15 inch sewer main to be extended from south of Highway 66 north to the southwest Sorrento Addition I Annexation Impact Report Landmark Engineering Ltd. 5/10/2007 corner of the Sorrento Addition development. Funding for the construction has been contributed to the St. Vrain Sanitation District and construction should begin in the spring of 07. d. The following entities are currently providing services within the Sorrento Addition vicinity. SCHOOL DISTRICT: St. Vrain Valley School District FIRE DISTRICT: Mountain View Fire District SANITATION DISTRICT: St. Vrain Sanitation District WATER DISTRICT: Northern Colorado Water Little Thompson Water District ELECTRIC POWER: United Power e. The applicant plans to develop 175 residential units in the form of single family detached residential units within the area to be annexed. Housing Type No. of Units Single Family Detached 175 School Grade No. of Students Elementary(0.35) 62 Junior High (0.14) 25 Senior High (0.17) 30 Total 117 Students As has been approved by the School District, a 'cash-in-lieu' fee of approximately $645.00 per lot will be assessed at the time of building permit in lieu of land dedication to the School District for a school site. Sorrento Addition 2 Annexation Impact Report Landmark Engineering Ltd. 5/10/2007 war 'A j I �A 1 f lira 1 �� } . �C/ i n.att: • / ; sato. '`$ ' ' J Sli'PROJEC' '. .• r.• -- - ,• ; lI I R.VRNM xFIR iN�M � ;�.. .- - fl .%.%':- - �� (- . V • • • ' viciwi r MAP 1"•2000' Sorrento Addition 3 Annexation Impact Report Landmark Engineering Ltd 5//0/2007 Hello