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Home My WebLink About20163188.tiffCOLORADO Department of Public Health & Environment Dedicated to protecting and improving the health and environment of the people of Colorado June 26, 2018 Board of County Commissioners Weld County 1150 O Street PO Box 758 Greeley, CO 80632 Re: Recommendation of Approval with Conditions Application for Certificate of Designation North Weld Landfill, Unit 2 SW/WLD/NWC 2.1 Members of the Board, RECEIVED JUL 022018 WELD COUNTY COMMISSIONERS On January 13, 2017, the Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division (Division), received from Weld County, Colorado, a referral notification requesting the Division's review of an engineering design and operations plan (EDOP) for a Certificate of Designation (Application) for operation of the North Weld Landfill, Unit 2 (Facility) near Ault, Colorado. The applicant, Waste Management Disposal Services of Colorado, Inc., is to be the owner and operator of the proposed Facility. The EDOP was received at the Division on January 13, 2017. The Division conducted a completeness review and provided a letter dated February 9, 2017 with a finding that the EDOP was complete in addressing the requirements. The Division reviewed the EDOP to determine its compliance with the requirements set forth in the Solid Waste Disposal Sites and Facilities Act, Title 30, Article 20, parts 1 and 10 (Solid Waste Act) of the Colorado Revised Statues (CRS), as amended, and with the regulations promulgated there under: the Regulations Pertaining to Solid Waste Sites and Facilities, 6 CCR 1007-2, Part 1 (Solid Waste Regulations). In accordance with the Solid Waste Statute, CRS 30-20-103, the Division conducted comprehensive technical evaluation of the EDOP. Division comments were developed in coordination with the Weld County Department of Public Health and Environment (WCDPHE). These comments were submitted to the applicant on May 4, 2017. On November 22, 2017, the applicant delivered a complete revision of the EDOP, identified as Revision 1, dated November 17, 2016. On May 16, 2018, the Division issued follow-on technical comments that were minor corrections or clarifications. The applicant Cornw►(4,v►tc,a u CC: RiJ SF)2°PL`Kb) 61-05-18 ao 1CO- 318'8' PLO -7? -7 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe John W. Hickenlooper, Governor Larry Wolk, MD, MSPH, Executive Director and Chief Medical Officer Board of County Commissioners Recommendation for Approval with Conditions Application for Certificate of Designation North Weld Landfill, Unit 2 June 25, 2018 Page 2 issued replacement pages for the Revision 1 EDOP on May 18, 2018 that addressed all remaining corrections and clarifications. On May 24, 2018, the Division published a notice in the North Weld Herald requesting written public comments on the proposed North Weld Landfill, Unit 2. The public comment period ended on June 24, 2018, and the Division received no comments. It is the determination of the Division that the North Weld Landfill, Unit 2 can comply with technical, environmental, and public health standards of the Solid Waste Act and the Solid Waste Regulations if the Facility is monitored and operated as stated in the CD Application and associated EDOP, Rev. 1 and with the Division's conditions of recommendation as stated below in this letter. Based on our review and determination, the Division recommends, with conditions, that the Facility may be approved by Weld County based on these and any local criteria. The final revised North Weld Landfill, Unit 2 facility Application including the final revised EDOP and final resolution containing the CD must be placed in the Facility's operating record. Our recommendation for approval of the Application including the final revised EDOP (Rev. 1) has the following conditions that must be incorporated into the CD if issued by Weld County: 1. Compliance with this CD requires the owner /operator comply with the attached EDOP and any future Department -approved EDOP conditions, including both Department - approved amendments to the EDOP and Department -approved stand-alone plans necessary to comply with the Solid Waste Act and Regulations. Violation of the EDOP as so amended constitutes a violation of this CD. This CD need not be amended upon EDOP amendment unless required by Weld County. 2. CDPHE reserves the right to make unilateral modifications to the EDOP language and conditions at any time during the life of the facility, including during the post closure care period. CDPHE will consult with the County prior to doing so. 3. The Financial Assurance Plan, including independent third party or referenced cost estimate, shall be submitted to the Division for review and approval. In addition, the financial assurance mechanism must be in -place and approved by the Division prior to acceptance of waste material at the site. Please note that pursuant to the requirements of Section 1.8.3 of the Solid Waste Regulations, the closure and post - closure cost estimate must be adjusted annually to account for inflation or deflation by using the implicit price deflator for the gross domestic product. Additionally, the Facility must replace the original cost estimate every five (5) years unless otherwise required by the Division. Both the annual adjustment and the 5 -year update cost estimates must be submitted to the Division for review and approval. 4. Pursuant to C.R.S. 25-15-321 Waste Management shall grant to the Division an Environmental Covenant placing environmental use restrictions on the site to ensure protection of human health and the environment following closure of the solid waste disposal site and facility. 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe John W. Hickentooper, Governor I Larry Wotk, MD, MSPH, Executive Director and Chief Medical Officer Board of County Commissioners Recommendation for Approval with Conditions Application for Certificate of Designation North Weld Landfill, Unit 2 June 25, 2018 Page 3 5. The Facility must comply with the public health and environmental laws, standards, and regulations of the Department and all other applicable state, federal, and local rules, and ordinances, including requirements of the Air Pollution Control Division and Water Quality Control Division, which were outside the scope of the review conducted by the Solid Waste Program. As required by 30-20-104(3)(a) and (3)(b), Weld County is obligated to notify its citizens and conduct a public hearing regarding the proposed solid waste facility. Please forward a copy of the Weld County final resolution concerning the CD issuance or denial to the Division. Should you have any questions addressing the determinations herein please contact Andy Todd at (303) 691-4049 or by email at Andrew.Todd©state.co.us. Sincerely, 1 0� Andy Todd Solid Waste Permitting Unit Solid Waste and Materials Mgmt Program Hazardous Materials Waste Mgmt Division ec: Kim Ogle Ben Frissell Tom Schweitzer Bill Hedberg Jeff Rusch Jy`Kenderson Solid Waste Permitting Unit Leader Solid Waste and Materials Mgmt Program Hazardous Materials Waste Mgmt Division Weld County Planning Department Weld County Department of Health and Environment Waste Management Waste Management Golder Associates 4300 Cherry Creek Drive S., Denver, CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe John W. Hickenlooper, Governor I Larry Wolk, MD, MSPH, Executive Director and Chief Medical Officer Esther Gesick From: Hayley Brown Sent: Tuesday, October 04, 2016 4:35 PM To: Esther Gesick Cc: Kim Ogle Subject: FW: North Weld Landfill Paving Improvements Attachments: 1538880 LTR-FNL NWLF Haul Rd Improvements 22SEP16.pdf Hello Esther, Can you please put this in Tyler as Correspondence for USR-895 PL0777? Thank you! Hayley Brown Engineer I Planning Department 1555 N 17th Ave Greeley, CO 80631 phone: (970) 400-3552 fax: (970) 304-6498 Confidentiality Notice: This electronic transmission and any attached documents or other writings are intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. If you have received this communication in error, please immediately notify sender by return e-mail and destroy the communication. Any disclosure, copying, distribution or the taking of any action concerning the contents of this communication or any attachments by anyone other than the named recipient is strictly prohibited. From: Rusch, Jeffrey [mailto:Jeffrey_Rusch@golder.com] Sent: Thursday, September 22, 2016 4:15 PM To: Hayley Brown <hbrown@co.weld.co.us> Cc: Bill Hedberg <bhedberg@wm.com>; Schweitzer, Tom <tschweit@wm.com>; Kim Ogle <kogle@co.weld.co.us> Subject: RE: North Weld Landfill Paving Improvements Hayley — On behalf of Waste Management Disposal Services of Colorado, Inc., Golder is pleased to provide Weld County with the attached letter summarizing the results of the supporting hydrologic and hydraulic calculations for the proposed haul road pavement improvements work. (tW' ; /0- iz -0'0lb 1 2016-3188 PL0777 A hard copy of this letter and attached figure was also sent out to your attention this afternoon. If you have any questions on these calculations, feel free to contact myself or Tom Schweitzer. Thanks, Jeff Jeff Rusch, P.E., LEED AP I Senior Engineer I Golder Associates Inc. 44 Union Boulevard, Suite 300, Lakewood, Colorado, USA 80228 T: +1 (303) 980-0540 I D: +1 (720) 962-3435 I C: +1 (612) 702-9423 I F: +1 (303) 985-2080 I E: Jeffrey Rusch@golder.com I www.golder.com Work Safe, Home Safe This email transmission is confidential and may contain proprietary information for the exclusive use of the intended recipient. Any use, distribution or copying of this transmission, other than by the intended recipient, is strictly prohibited. If you are not the intended recipient, please notify the sender and delete all copies. Electronic media is susceptible to unauthorized modification, deterioration, and incompatibility. Accordingly, the electronic media version of any work product may not be relied upon. Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation. Please consider the environment before printing this email. From: Hayley Brown [mailto:hbrown@co.weld.co.us] Sent: Friday, September 09, 2016 8:21 AM To: Schweitzer, Tom Cc: Kim Ogle; Hedberg, Bill Subject: RE: North Weld Landfill Paving Improvements Tom, As discussed today, this is most of what we need but there a few more items that I need: 2 Calculations that show the increased quantity of runoff for the design storm (100 year, 24 hour storm) for the change from gravel to asphalt for the area and the resulting change in volume Information on how this flow will get to the pond — the USR attached is unclear to me on how the flow in the area of the road gets to the pond The report needs to be stamped as well as signed If you have any questions, please feel free to contact me. Thank you! Hayley Brown Engineer I Planning Department 1555 N 17th Ave Greeley, CO 80631 phone: (970) 400-3552 fax: (970) 304-6498 Confidentiality Notice: This electronic transmission and any attached documents or other writings are intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. If you have received this communication in error, please immediately notify sender by return e-mail and destroy the communication. Any disclosure, copying, distribution or the taking of any action concerning the contents of this communication or any attachments by anyone other than the named recipient is strictly prohibited. From: Schweitzer, Tom [mailto:tschweit@wm.com] Sent: Tuesday, September 06, 2016 9:40 AM 3 To: Hayley Brown <hbrown@co.weld.co.us> Cc: Kim Ogle <kogle@,co.weld.co.us>; Bill Hedberg <bhedberg@wm.com> Subject: North Weld Landfill Paving Improvements Hi Hayley, Following up from Bill's recent discussion with you regarding paving plans at North Weld, attached is a letter that provides an overview of the suitability of the on -site retention pond for handling any additional run off resulting from an increase in impervious area due to the paving. Please don't hesitate to contact me with any questions. Hayley and Kim, please let me know if you would also like to receive a paper copy of the attachment. Thanks! Tom Recycling is a good thing. Please recycle any printed emails. 4 Golder Associates September 22, 2016 Ms. Hayley Brown Weld County Engineering 1555 N. 17th Avenue Greeley, CO 80631 Project No. 1538880 RE: SUPPORTING HYDROLOGIC AND HYDRAULIC CALCULATIONS; NORTH WELD LANDFILL PAVING IMPROVEMENTS Dear Ms. Brown: On behalf of Waste Management Disposal Services of Colorado, Inc. (WMDSC), Golder Associates Inc. (Golder) is pleased to provide Weld County Engineering (the County) with this letter summarizing the hydrologic and hydraulic calculations performed in support of the proposed paving improvements at the North Weld Landfill. As previously discussed between the County and WMDSC, WMDSC plans to pave approximately 1,000 feet of the main haul road along the west side of the landfill. Golder understands that the County requested additional information on potential drainage impacts on site drainage structures related to the increase in impervious area. On September 6, 2016, Senior Engineer Tom Schweitzer with WMDSC provided the County with a letter providing historical information on the design (storage capacity) and construction of the existing stormwater retention pond that ultimately receives stormwater runoff from the haul road to be paved. In response, the County requested additional hydrologic calculations supporting the proposed paving improvements. This purpose of this letter is summarize the scope and results of the hydrologic and hydraulic calculations performed to support the paving improvements. 1.0 STORMWATER MANAGEMENT SYSTEM DESIGN The stormwater management system for the North Weld Landfill was designed as part of the development of the Updated Design and Operations (D&O) Plan for the North Weld Sanitary Landfill originally prepared by Rust Environment & Infrastructure, Inc. in January 1996, and revised by WMDSC in November 1997. Runoff from closed landfill slopes and surrounding run-on areas is collected by permanent perimeter channels and conveyed to a retention pond located in the southeastern corner of the property. The highpoint of the property is in the northwest corner. Runoff from the primary haul road is initially collected in the western perimeter channel, as shown in the attached Figure 1. In 2010, Golder modified the facility hydrologic and hydraulic calculations to capture stormwater runoff from west of the primary haul road and convey it to the landfill perimeter channel via an 18 -inch culvert crossing beneath the primary haul road (Golder 2010). Golder subsequently modified the calculations again in 2013 to replace approximately 100 feet of perimeter channel with a 36 -inch -diameter culvert to allow for the development of a landfill access road across the channel alignment and to incorporate several changes to the perimeter channel alignment as a result of as -built liner grading plans (Golder 2013). The locations of these culverts are shown in the attached Figure 1. is\15\1538880\0100\011Maul rd imp. 22sep16\1538880 itr-fnl nwlf haul rd improvements 22sep16.docx Golder Associates Inc. 44 Union Boulevard, Suite 300 Lakewood, CO 80228 USA Tel: (303) 980-0540 Fax: (303) 985-2080 www.golder.com Golder Associates: Operations in Africa, Asia, Australasia, Europe, North America and South America Golder, Golder Associates and the GA globe design are trademarks of Golder Associates Corporation Ms. Hayley Brown September 22, 2016 Weld County Engineering 2 1538880 2.0 HYDROLOGIC AND HYDRAULIC CALCULATIONS 2.1 Scope As the new paved section of the haul road will report to the culverts and perimeter channels, the affected channel sections and culvert crossings were re-evaluated to demonstrate that the structures will have sufficient conveyance capacity. As the perimeter channel discharges into the existing retention basin in the southeast corner of the property, the increased runoff volume was also estimated in order to verify that the basin will have sufficient storage capacity. 2.2 Methodology Drainage basins along the main haul road, which include the proposed pavement area, were delineated using site topography provided by WMDSC. The paved roadway was assumed to be crowned perpendicular to the centerline, with runoff from one basin (A1) draining west off the pavement, then south through a drainage ditch and ultimately reporting to the existing 18 -inch high -density polyethylene (HDPE) culvert under the haul road and the other basin (A2) draining east off the pavement into the landfill perimeter channel and continuing south to the existing 36 -inch HDPE culvert under the landfill access road. Consistent with the original hydrologic calculations, the Soils Conservation Service (SCS) methodology was used as the basis of the hydrologic modeling. SCS curve numbers and rainfall data were referenced from the previous Golder calculations (Golder 2010 and 2013). HEC-HMS (USACE 2013) software was used to calculate peak discharges. For hydraulic analysis of the perimeter channel, Manning's equation flow calculation spreadsheets previously used for the channel design were updated for the purposes of this modification. The Federal Highway Administration's HY-8 culvert analysis program (FHWA 2014) was used to evaluate capacity of the previously -deigned culvert crossings. 2.3 Results The results of the HEC-HMS hydrologic analysis are presented in Table 1 below. Table 1: Peak Discharge Summary Basin Drainage Area (acres) . Basin (%) Imperviousness 100-Yr, (cfs) 24 -Hr Peak Discharge Al (West) 2.2 14 1 7 A2 (East) 2.2 21 6 Due to a lack of detail provided in the original design calculations and supporting figures presented in the D&O Plan, it is unclear whether runoff from the main haul road and surrounding area west of the road was included in the original channel design. Therefore, it was conservatively assumed that these basin areas along the haul road and corresponding peak flows were not previously included in the areas and runoff volumes presented in the 1997 D&O Plan. As such, the calculated peak flows presented in Table 1 were added directly (no routing) to the perimeter channel flowrates provided in the 1997 calculations to determine if the as -designed perimeter channels and culvert crossings are adequate to accommodate the additional runoff from the pavement improvements. All channel reaches and culvert inlets as currently sized and constructed have adequate capacity to accommodate the additional discharge from the paved haul road and surrounding runoff areas shown in Figure 1 while maintaining a minimum of one foot of available freeboard. The additional discharge will result in an increase in total runoff volume of approximately 1.0 acre-feet requiring storage in the retention basin. As outlined in the retention basin documentation previously provided to the County by WMDSC, the design runoff volume reporting to the basin is 22.6 acre-feet prior is\15\1538880\0100\0110\haul rd imp. 22sep16\1538880 Itr-fnl nwlf haul rd improvements 22sep16.docx C-4‘ Golder Associates Ms. Hayley Brown Weld County Engineering September 22, 2016 3 1538880 to the pavement improvements work. Conservatively assuming that the runoff from the main haul road and surrounding area west of the road was not previously included in the basin design, the total estimated runoff volume requiring storage will be 23.6 acre-feet. As constructed, the available volume for stormwater retention in the basin is 42.2 acre-feet (10.8 acre-feet set aside for sediment storage in the design calculations and 31.4 acre-feet of stormwater storage). This available storage volume does not include the storage volume set aside for maintaining one foot of freeboard (7.1 acre-feet) per Weld County Code requirements. Complete versions of the supporting hydrologic and hydraulic calculations are not attached to this letter. Complete copies of the calculations can be submitted to the County if required upon request. Please let me know if you have any questions regarding these calculations. Best Regards, GOLDER ASSOCIATES INC. Jeff Rusch, PE Senior Engineer cc: Tom Schweitzer, Waste Management Disposal Services of Colorado, Inc. Bill Hedberg, North Weld Landfill Kim Ogle, Weld County Planning Enclosures: Figure 1 JARJap i:\15\1538880\010010110\haul rd imp 22sep16\1538880 Itr-fnl nwlf haul rd improvements 22sep16 docx Golder Associates LEGEND 361;0 EXISTING GROUND CONTOUR It -MSII Emu' NO ROADS -� -� PERIMETER CHANNEL ALIGNMENT 2 PERIMETER CHANNEL REACH LOCATION AND ID BASIN DELINEATION PROPOSED HAUL ROAD PAVED AREA • CONCENTRATION POINT BASIN ID WATERSHED AREA (ACRES) 0 200 400 1•x400' FEET CLIENT WM. PROJEC' NORTH WELD LANDFILL WELD COUNTY, COLORADO MAIN HAUL ROAD IMPROVEMENTS li T' RUNON BASIN DELINEATION AND SELECT PERIMETER CHANNEL LOCATIONS CONSULTANT CPs, YWY MM -DO 201609-21 DESIGNED SPS PREPARED JHR REVIEWED OMW APPROVED JAR PROJECT NC CONTROL 1538880 0002 REV A FIGURE 1 Hello