Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals (RFP)

Transcription

1 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals (RFP) Proposal Advertisement: April 20, 2018 Proposal Deadline: May 18, 2018, 10:00 a.m. M.T. Project Mission The Williams Fork River Restoration Project (project) serves as compensatory mitigation for the Gross Reservoir Expansion Project (or Moffat Collection System Project) described in the 2017 Final Mitigation Plan and required by the U.S. Army Corps of Engineer s (Corps) Section 404 Permit. As such, the project must demonstrate an improvement in aquatic habitat based on the Stream Functions Pyramid Framework (Harman et al. 2012) and measured by application of the the Habitat Suitability Index (HSI) curves for the focal species rainbow trout (Raleigh et al. 1984). The HSI method was developed by the U.S. Fish and Wildlife Service (USFWS) and rates physical stream characteristics, channel hydrology, and water quality, based on important life cycle variables of targeted fish species. Request for Proposals Denver Water is soliciting proposals from qualified firms for a fluvial geomorphologist/fisheries biologist/ecologist or other related professional to perform baseline pre-construction and post-construction monitoring and reporting of the project according to the Corps compensatory mitigation requirements. The responsibilities of the Stream Monitor are presented herein with instructions for preparing a complete proposal. Role and Responsibility of the Stream Monitor The Stream Monitor will be responsible for Tasks 1-4 identified in Section 2 - Scope of Work. Project Background The project includes restoration activities on a total of approximately 2.08 river miles with two distinct restoration reaches above and below the Williams Fork Reservoir in Grand County, Colorado. These two reaches were selected based on the potential for ecological uplift and increased aquatic functions. Restoration activities at the Upper Reach (1.2 miles) and Lower Reach (0.88 mile) will result in improved low flow conditions, instream diversity, channel stability, and streamside vegetation. The Upper and Lower Reaches occur on land owned and managed by Denver Water. Denver Water is in the process of retaining a qualified contractor responsible for the design and construction of the project. Construction of the project will be in two phases: Construction of the Lower Reach will occur in 2018, and Construction of the Upper Reach will occur in Due to Colorado Parks and Wildlife s (CPW) construction restrictions for trout spawning on the Williams Fork River, construction activities must occur in the summer following peak runoff and be completed by October 1. Page 1 of 7

2 April 20, 2018 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals Project Goals and Objectives The overall goal of the project is to restore aquatic resource functions and habitat complexity to two reaches of the Williams Fork River identified in Appendix A. This goal will be met through the following five (5) specific objectives. Progress towards acheiving each objective will be measured using the Habitat Suitability Index (HSI) for the focal species rainbow trout. Successful completion of the project will occur when the HSI scores for each objective satisfy the performance standards required in Section of Appendix A. 1. Low Flow Channel Condition: re-establish appropriate channel geometry in balance with the current flow regime to establish a defined low flow thalweg. 2. Habitat and Bed Form Diversity: increase aquatic habitat and bedform diversity by establishing natural riffle/pool complexes based on typical, natural sequencing. 3. Habitat and Bed Form Diversity: increase aquatic habitat and bedform diversity by improving pool condition and instream cover. 4. Habitat and Bed Form Diversity: improve pool quality. 5. Riparian Vegetation: increase riparian vegetation adjacent to the channel to provide overhead cover, shading and reduce sediment loading to the stream. Section 1 Administrative Requirements 1.1 Project Contact Information Any requests for clarification or additional information regarding submission of this RFP shall be submitted to Jessica Alexander (jessica.alexander@denverwater.org or ) by April 30, Proposal Submission Responses shall be in the format noted. Denver Water reserves the right to disqualify any response submitted incorrectly. Respondents are requested to submit: Three (3) hard copies of the Respondent s proposal. One (1) electronic copy of the proposal provided as a pdf on DVD or flash drive. Proposals are due no later than 10 am, local time, May 18, Late proposals will not be reviewed or scored. Responses shall be addressed as follows: Project Title: Attention: Address: Williams Fork River Restoration Project, RFP for Pre- and Post-Construction Monitoring Jessica Alexander, Environmental Scientist Denver Water External Affairs Division, Administration Building 1600 West 12th Avenue Denver, Colorado Submittal Instructions: 1. Proposals may be either mailed or hand-delivered. If the proposal is sent by mail, please allow extra time for delivery before the deadline. (Note: No ed or faxed proposals will be accepted.) 2. Proposals shall contain the signature of a duly authorized officer or agent of the Respondent s company empowered with the right to contractually bind the Respondent. Page 2 of 7

3 April 20, 2018 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals 3. Proposal shall be sealed and addressed as stated previously to ensure confidentiality of the information prior to the submission date and time. Denver Water is not responsible for premature opening of proposals improperly labeled. 4. Proposals become the property of Denver Water upon receipt. The content of proposals will be kept confidential until an award is made, after which the content will no longer be kept confidential, except as provided herein. 5. Proposals may be withdrawn or modified in writing prior to the proposal submission deadline. Proposals that are modified shall be sealed and resubmitted according to the aforementioned instructions prior to the proposal submission deadline. 1.3 Proposal Requirements The proposal must contain all of the following information, in the same sequence as presented below. Each proposal should provide a straightforward and concise presentation adequate to satisfy the requirements of this RFP. Proposals must be limited to 10 pages, not including resumes. 1. Cover Letter a. Include a cover letter that introduces your company, summarizes your firm s qualifications, and provides the principal contact information for this RFP including name, address, , and telephone number. 2. Approach to Pre- and Post-Construction Monitoring and Reporting b. Provide a description of your understanding of the Corps monitoring and reporting requirements specified in Appendices A and B. Describe your understanding of and familiarity with the Stream Functions Pyramid Framework (Harman et al. 2012) and the Habitat Suitability Index (HSI) field measurement method (Raleigh et al. 1984) for determing ecological uplift in streams. c. Provide a description of your approach to accomplishing the Scope of Work (refer to Section 2). d. Provide a schedule of work by task. 3. Budget or Cost Estimate Provide an itemized budget listed out by task, including: i. A manpower labor estimate via a detailed breakdown by labor type/hours ii. A valid 2018 labor rate sheet including how indirect costs will be invoiced iii. A proposed labor rate escalation approach for 5 years and future years to be negotiated 4. Key Staff and Previous Experience on Similar Projects 1.4 Award of Contract Provide a description of similar work previously completed. Provide a list of the principal individuals who will work on this project along with resumes of their relevant Section 404 monitoring and reporting experience. Agreements may be negotiated with Respondents whose proposal is determined to be most responsive to Denver Water s needs and most advantageous to Denver Water, considering the factors based on the criteria described in Section 4, all as solely determined by Denver Water. Award of an Agreement may be Page 3 of 7

4 April 20, 2018 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals made after proposals are received and without interviews. Therefore, proposals shall be reviewed on the qualifications, technical experience, cost, and proposed financial terms. Denver Water reserves the right to reject any or all proposals. Once a proposal for Stream Monitor is selected, the final scope of work will be agreed upon between the selected firm and Denver Water and contained in a Professional Services Agreement. Denver Water reserves the right to extend the Agreement, based on the Stream Monitor s performance, with future tasks negotiated as the project progresses. 1.5 Respondent Responsible For Proposal Costs Denver Water is not liable for any cost incurred by any Respondent associated with the preparation of a proposal or the negotiation of an Agreement for services prior to the issuance of an Agreement. The Respondent is responsible for costs associated with responding to the RFP including costs related to site visit(s) and estimate preparation(s) for work authorized under the Agreement. Respondents may be asked to present their proposals to Denver Water s representatives at Denver Water offices. The Respondents shall bear the costs for such presentations. 1.6 Binding Proposal Respondents are advised that proposals shall be binding upon the Respondent for sixty (60) days from the proposal due date. A Respondent may withdraw or modify their proposal any time prior to the proposal due date by a written request, signed in the same manner and by the same person who signed the proposal. 1.7 Notification Each Respondent submitting a proposal in response to this RFP will be notified in writing as to acceptance or rejection of their proposal. Denver Water plans to release such letters within two weeks of the proposal submittal date. Denver Water may delay this action if it is deemed to be in the best interest of Denver Water. 1.8 Right to Reject Proposals and Negotiation Denver Water reserves the right to reject any and all proposals and to waive any formality in proposals received, to accept or reject any or all of the items in the proposal, if it is deemed in Denver Water s best interest. Denver Water reserves the right to negotiate any and all elements of the proposal, if such action is deemed to be in the best interest of Denver Water. 1.9 Confidentiality Proposers acknowledge that Denver Water may be required to disclose any or all of the documents submitted with a Response, pursuant to the Colorado Open Records Act, C.R.S , et seq. Under C.R.S (3) (a) (IV), Denver Water may deny inspection of any confidential commercial or financial information furnished to Denver Water by an outside party. Therefore, a Respondent shall clearly designate any documents submitted with its Response that the Respondent deems proprietary or confidential, to aid Denver Water in determining what should be disclosed in the event of a request for documents under the Colorado Open Records Act. Proposals submitted and terms and conditions specified in each Respondent s response shall remain the property of Denver Water. Page 4 of 7

5 April 20, 2018 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals Section 2 Scope of Work The selected firm and Denver Water will enter into a Professional Services Agreement based on project milestones and performance. A description of the project habitat improvement elements and performance standards is provided in Appendix A Excerpt of Section 1.3 from Denver Water s Final Mitigation Plan for the Moffat Collection System Project. The Corps monitoring and reporting requirements are found in Appendix B - Corps Regulatory Guidance Letter No , October 10, The Stream Monitor will perform the following monitoring and reporting (Tasks 1-4) consistent with the requirements in Appendices A and B. 2.1 Task 1 Pre-Construction (Baseline Conditions) Site Survey Prior to the start of construction of the Lower Reach (August 1, 2018) and Upper Reach (est. July 23, 2019), the Stream Monitor must conduct a pre-construction (baseline conditions) site survey to establish the following at each reach: i. Existing Stream Function. Establish sampling sites in which to measure the HSI parameters for stream function at the Upper and Lower Reaches [i.e. average thalweg depth (HSI V4), percent pool habitat (HSI V10), and average percent vegetational ground cover and canopy closure along the stream (HSI V11)]. Collect baseline measurements for these three HSI parameters. ii. Existing Riffle/Pool Complexes. Evaluate the number and location of existing riffle and pool features at the Upper and Lower Reaches. iii. Existing Pool Quality. Evaluate the existing pool quality at the Upper and Lower Reaches according to the percent of first, second, and third class pools (HSI V15). iv. Photo Points. Using GIS, establish photo points and take baseline photos to be used to document site conditions before, during, and after construction of the Upper and Lower Reaches. Deliverables: Provide to Denver Water a pre-construction (baseline conditions) summary report of the Lower Reach by September 30, 2018 and the Upper Reach by September 30, Include map(s) identifying the sample site locations. All HSI scores must relate to the performance standards established in Section of the Final Mitigation Plan (Appendix A). 2.2 Task 2 Project Completion (As-Built Condition) Site Survey Within one (1) week following the completion of construction on each phase of the project (the Upper and Lower Reaches), the Stream Monitor must conduct an as-built condition survey to evaluate the following: i. Stream Function. For each of the defined HSI sampling sites at the Upper and Lower Reaches [i.e. average thalweg depth (HSI V4), percent pool habitat (HSI V10), and average percent vegetational ground cover and canopy closure along the stream (HSI V11)], collect measurements to document the as-built condition. ii. Riffle/Pool Complexes. Evaluate the number and location of riffle and pool features at the Upper and Lower Reaches to document the as-built condition. iii. Pool Quality. Evaluate the pool quality at the Upper and Lower Reaches according to the percent of first, second, and third class pools (HSI V15) to document the as-built condition. iv. Photo Points. At the established photo points at Upper and Lower Reaches, take photos to document the as-built condition. Page 5 of 7

6 April 20, 2018 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals Deliverables: Provide to Denver Water an as-built conditions summary report and map(s) of the Lower Reach by November 30, 2018 and the Upper Reach by November, 30, All HSI scores must relate to the performance standards established in Section of the Final Mitigation Plan (Appendix A). 2.3 Task 3 Post-Construction Annual Site Surveys (5-Year Monitoring) Per Denver Water s 404 Permit, beginning one (1) year after the completion of the project for a total of five (5) years or until the Performance Standards have been met and the monitoring requirements are fulfilled, the Stream Monitor will return to the project site to collect the data described above in Task 2. All post-construction annual site surveys should refect the phased construction schedule, with the Lower Reach construction in 2018 and the Upper Reach construction in Beginning in 2020, postconstruction annual site surveys for both reaches would be combined. 2.4 Task 4 Post-Construction Annual Reporting The annual report shall contain the post-construction monitoring results and must adhere to the Corps requirements as described in Appendix B Corps Regulatory Guidance Letter No , October 10, All post-construction annual reporting should reflect the phased construction schedule, with the Lower Reach construction in 2018 and the Upper Reach construction in Beginning in 2020, postconstruction annual reporting for both reaches would be combined. Deliverables: An annual post-construction summary report and map(s) will be provided to Denver Water by November 1st each year. Section 3 Project Schedule 3.1 Tentative Schedule The following schedule of project milestones is provided for planning purposes. Milestone Date Advertisement of RFP April 20, 2018 Proposals due Owner Board Meeting and Notice of Award June 13, 2018 Notice to Proceed June 20, 2018 Construction of Lower Reach - Start (Est)* August 1, 2018 May 18, 10:00 AM MT Construction of Lower Reach - Completion October 1, 2018 Construction of Upper Reach - Start (Est)* July 23, 2019 Construction of Upper Reach - Completion October 1, 2019 *Due to CPW s construction restrictions for trout spawning on the Williams Fork River, construction of the project must occur in the summer following peak runoff and be completed by October 1. Page 6 of 7

7 April 20, 2018 Williams Fork River Restoration Project Pre- and Post-Construction Monitoring Request for Proposals Section 4 Selection Criteria Denver Water will perform a complete review of the Proposals received according to the following selection criteria. Once a Proposal is selected, the final scope of work will be negotiated between the selected firm and Denver Water and defined in a Professional Services Agreement. Selection will be based on a weighted system giving consideration to the Respondent s Proposal as shown in Table 1 below. A team of Owner subject matter experts will review the Proposals and make a selection based on the criteria, weight, and standards presented below. Each criterion is assigned a score from 1 to 10, with 1 being a poor rating, 5 being an average rating, and 10 being an outstanding rating. All criteria will be multiplied by the associated weight to give a weighted criteria score. The weighted criteria scores will be summed for a cumulative score. The maximum possible cumulative score is 100. Consideration will be given to MWBE participation as part of the Proposal Cost criteria. Table 1 Weighted Selection Criteria Weight Criteria Standard 3 5 Proposed Approach Key Staff Experience Proposals will be evaluted for how well they demonstrate a thorough understanding of the goals and objectives of the project and include a well thought out execution plan of how the Respondent will meet the project objectives and satisfy the field and reporting work according to the Corps requirements in Appendices A and B. Key staff resumes and experience will be evaluated for how well they demonstrate relevant and successful experience working on similar projects in the Colorado Rocky Mountain region that adhere to the Corps monitoring and reporting requirements. 2 Costs and Schedule The costs and schedule will be evaluated for reasonableness, milestones, completeness, quality, thoroughness, understanding, and balanced activities. Schedules that do not meet the specified milestones in Section 3 may not receive any points in this category. Appendices A. Section 1.3 excerpt from Denver Water s Final Mitigation Plan for the Moffat Collection System Project (Corps File No. NWO DEN) dated July 8, 2017 B. Corps Regulatory Guidance Letter No , October 10, Page 7 of 7

8 Appendix A Excerpt - Section 1.3 Only Final Mitigation Plan for the Moffat Collection System Project Corps File No. NWO DEN Prepared For: U.S. Army Corps of Engineers Denver Regulatory Office 9307 S. Wadsworth Blvd. Littleton, CO June 8, 2017 Prepared By:

9 Table of Contents Executive Summary... iii Project Description... iii Project Location... iii Chapter 1: Compensatory Mitigation Plan Purpose Four Mile Creek Fen Mitigation Bank Compensatory Mitigation for Wetland Impacts (East Slope) Impact Area Characterization Mitigation Objective Site Selection Baseline Information Determination of Credits South Boulder Creek Restoration Project - Compensatory Mitigation for Other Waters of the U.S Impacts (East Slope) Impact Area Characterization Mitigation Objective Site Selection Site Protection Instrument Baseline Information Determination of Credits Mitigation Work Plan Maintenance Plan Performance Standards Monitoring and Reporting Long-Term Management Plan Adaptive Management Plan Financial Assurances Colorado Headwaters Mitigation Project Compensatory Mitigation for Incremental Effects to Aquatic Resources (West Slope) Impact Area Characterization Mitigation Objective Site Selection Site Protection Instrument Baseline Information Determination of Credits Mitigation Work Plan Maintenance Plan Performance Standards Monitoring and Reporting Long-Term Management Plan Adaptive Management Plan Financial Assurances i

10 Chapter 2: Applicant-Proposed Mitigation for the 404 Permit, and Other Project Mitigation and Enhancements for the Corps Consideration Purpose Elements of this Chapter Applicant-Proposed Mitigation Measures for the 404 Permit Applicant-Proposed Special Conditions Final Authorizations and Legal Requirements for the Corps Decision Agreements and Commitments Contributing to Overall Net Environmental Benefits from the Moffat Project Public Interest Review Factors Summary of Mitigation and Enhancement Commitments References Figures: Figure 1. Topographic Map of Impact Site Figure 2. General Physical Characteristics of South Boulder Creek Impact Site Figure 3. General Physical Characteristics of South Boulder Creek Riffle-Pool Complex Impact Site Figure 4. Topographic Map of South Boulder Creek Mitigation Site Figure 5. Aerial Image of South Boulder Creek Mitigation Site Figure 6. Stream Functions Pyramid Framework Figure 7. General Physical Characteristics of South Boulder Creek Mitigation Site Figure 8. Topographic Map of Williams Fork Mitigation Site Figure 9. Watershed Map of Williams Fork Mitigation Site Figure 10. Aerial Image of Williams Fork Mitigation Site Figure 11. Photos and Descriptions of the Williams Fork Mitigation Site Tables: Table 1. Summary of Level, Category and Function Parameters Selected for the SBCRP Table 2. Mitigation Objectives and Target Functions of the SBCRP Table 3. South Boulder Creek Restoration Project Key Components Table 4. SBCRP Summary of Measurement Methods for Annual Monitoring Table 5. HSI Parameter Ranking Table 6. Scale of Ecological Health: Colorado River Headwaters Table 7. Summary of Level, Category and Function Parameters Selected for the CHMP Table 8. Mitigation Objectives and Target Functions of the CHMP Table 9. CHMP Williams Fork Mitigation Site Key Components Table 10. CHMP Summary of Measurement Methods for Annual Monitoring Table 11. HSI Parameter Ranking Table 12. Public Interest Review Factors Table 13. Summary of Impacts, Mitigation, and Enhancement Measures for the Proposed Action Appendices: Appendix A. U.S. Fish and Wildlife Service Letter on South Boulder Creek Mitigation Site Appendix B. South Boulder Creek Mitigation Site Design Appendix C. Relevant Habitat Suitability Index Curves Appendix D. Denver Water Letter of Financial Assurances for Mitigation Appendix E. Williams Fork Mitigation Site Design ii

11 Moffat Collection System Project Final Mitigation Plan 1.3 Colorado Headwaters Mitigation Project Compensatory Mitigation for Incremental Effects to Aquatic Resources (West Slope) Impact Area Characterization The geographic scope of the Project s incremental effects to aquatic resources includes streams located in the upper Fraser River (10-digit HUC ) and upper Williams Fork River (10-digit HUC ) watersheds, within the Colorado Headwater Watershed Basin (8- digit HUC ). The Project s additional diversions from the headwater tributaries would decrease flows below the diversion structures on these streams and may cause incremental effects over time. Since the Project would cause impacts to aquatic resources collectively and incrementally on a watershed scale, Denver Water will provide compensatory mitigation using a watershed approach to offset such effects of the Project to the Colorado Headwater Watershed Basin (or Impact Area ). Currently, the headwater tributaries in the upper Colorado River watershed have already been affected by existing diversions in the Project Area as well as by many other local diversions that are not part of the Project. These streams have also been affected by other watershed-scale activities including development, the establishment and maintenance of roads, and culverts. Such activities have altered stream ecological processes, especially connectivity of upstream and downstream sections of stream including transfer of nutrients and sediment transport. However, the reductions in the number of days when water passes the diversions would reduce, to some extent, the transport of fish, benthic invertebrates, nutrients, and sediment from upstream to downstream sections, which would be a minor adverse effect (Corps 2014). An impact intensity analysis was conducted for the Colorado River headwater streams affected by the Project s diversions as part of the Final EIS. The intensity of impacts to aquatic biological resources was evaluated and categorized according to negligible, minor, moderate, or major impacts by stream segment. These impact intensity descriptions were primarily evaluated in terms of anticipated changes in flow and to modeled habitat or weighted usable area (WUA) for a given stream segment. The impact intensity analysis takes into account the magnitude of the change in a WUA metric, the risk of crossing an ecological threshold and causing a large change in fish or benthic macroinvertebrate species composition or abundance, and projected changes in water quality, temperature, channel geomorphology, sediment characteristics, and riparian vegetation (Corps 2014). The following is a summary of impacts to aquatic resources in the upper Colorado River watershed from reduced stream flows associated with the increased diversions from the Moffat Project. Overall, additional Moffat Tunnel diversions would occur in average and wet years and would be highly concentrated in May, June and July. There would be no additional diversions in dry years and below-average years when Denver Water already diverts the maximum amount physically and legally available (Corps 2014). 24

12 Moffat Collection System Project Final Mitigation Plan Physical Functions of Impact Area Overall, Project impacts to the physical functions of streams due to flow changes and sediment deposition or channel aggradation are expected to range from negligible to moderate. Currently, many of these small, headwater streams are physically degraded due to existing low flows and diversions. The reduction in stream flows anticipated from the Project in the rivers and tributaries where Denver Water has minimum bypass obligations may result in localized sediment deposition, which can affect the quality of aquatic habitats by filling in the interstitial spaces between gravel. The smaller tributaries downstream of Denver Water diversions, where no bypass flows are maintained, are currently impacted from aggradation and/or vegetation encroachment. The reduction in flow due to the Project may result in these stream segments being dry for longer periods and may result in large peak flows occurring less frequently, suggesting that existing aggradation and/or vegetation encroachment may be accelerated. The sedimentation typically appears to be concentrated near the diversion structures and are not pervasive throughout the stream segments. These streams all resume flows downstream of the diversion structures from groundwater, tributaries and wetlands during times when they are fully diverted (Corps 2014). The long-term impacts of the Project to the physical functions of these headwater streams are expected to be negligible because sufficient flows and large, infrequent flood events would remain and continue to mobilize sediment and retain long-term channel morphology (Corps 2014). Biological Functions of Impact Area The biological functions of aquatic resources in these Colorado River headwater streams may be described as currently near, at, or past ecological thresholds; however, such ecological thresholds have not been empirically determined for any of the stream segments within the Project Area. This is mostly due to the fact that each stream is likely to have its own ecological threshold level based on site-specific weather and environmental conditions. Therefore, for the Final EIS analysis, each stream segment was evaluated to determine if the proposed changes in flow from the Project would cause a given segment to cross a flow-based threshold. The Final EIS analysis applied two flow-based thresholds. The first was based on a study by Carlisle et al. (2010), where the risk of fish community impairment increased after a 60% reduction in maximum flows. However, the Final EIS findings revealed that there was considerable variability among the individual streams. The second flow-based threshold was based on a study by Baran et al. (1995), which showed that a 60% reduction in aquatic habitat measured as average annual WUA produced threshold effects on fish populations. However, the relationships between flow changes, habitat availability changes, and changes in fish populations are complex. Thus, when applied to ecological systems, the first flow-based threshold (60% reduction in average annual flows) does not necessarily create an equivalent reduction in habitat. Because the second flow-based threshold (Baran et al. 1995) showed the effects of a 60% reduction in a measure of average annual available habitat, not a 60% reduction in average annual flows (per Carlisle et al. 2010), the application of these thresholds in the Final EIS analysis assumed a 1:1 relationship between percent flow change and percent habitat loss. Since this is most often not the case in actual ecological systems, the estimates of threshold impacts used in the Final EIS are conservative (Corps 2014). 25

13 Moffat Collection System Project Final Mitigation Plan The Final EIS applied these two flow-based thresholds to examine the percent reduction in flow as one indicator of whether flow-based thresholds were crossed for each stream segment. If this were the case, the Final EIS assumed that there was a greater likelihood that an ecological tipping point may have been crossed as well. This is a conservative approximation, however, because it assumes that flow-based thresholds would have a direct relationship with the crossing of an ecological tipping point. The following classifications relative to the ecological tipping point were assigned to streams on the West Slope affected by the Project, refer to Table 6. These classifications are based on an analysis of the entire Project area for flow-based thresholds, as well as for population density data on fish and macroinvertebrates, which is summarized below. The FEIS Aquatic Resources Technical Report states that research has found a general pattern of higher fish density in small streams and lower density in larger streams and rivers; therefore, streams were analyzed according to size. Fish data from the individual streams in the Project Area were compared to a regional range of published fish densities used as a reference condition to evaluate historical changes in order to determine whether the individual streams had crossed an ecological tipping point (GEI 2013; Corps 2014). Not past tipping point. The fish data ranges in all years fall between the 25 th and 75 th percentiles of density estimates of Platts and McHenry (1988) or for larger streams. From 25 to 50 percent of the time, the mean density estimates are greater than or equal to 50th percentile estimates. The macroinvertebrate data indicate the presence of a healthy community (Corps 2014). The Project would not cause these streams to cross an ecological tipping point. However, the Project would reduce flows in these streams and would have a negligible to minor adverse effect on aquatic resources. Near tipping point. The fish data ranges fall between the 25 th and 75 th percentiles of density estimates of Platts and McHenry in less than half of the years. The mean density estimates are greater than or equal to the 50 th percentile estimates of Platts and McHenry less than 25% of the time. The macroinvertebrate data indicate a community that is degraded to some extent. There are no natural circumstances, such as naturally intermittent flows or unsuitable small stream size that would preclude the presence of fish. For example, trout are unlikely to overwinter successfully in streams with wetted widths of 1 meter or less with few deep pools (Corps 2014). The reduced flows associated with the cumulative impact of Full Use of the Existing System and the Project would likely cause these streams to cross the flow-based thresholds and likely cross an ecological tipping point. Past tipping point. Few to no fish present and degraded macroinvertebrate communities. The exception to this would occur in the case of extremely small streams that may not support fish year-round, even if water were not diverted (Corps 2014). 26

14 Moffat Collection System Project Final Mitigation Plan These streams are fully diverted under current conditions. In the future, under Full Use of the Existing System and with the Project, the period when these streams are fully diverted would be extended. The Project would have a minor adverse effect on the aquatic organisms in these streams because any organism that persists downstream of the diversion are tolerant of very low flows and because the proposed changes due to the Project are small in relation to historic diversions. However, the Project would likely incrementally further diminish the condition of the aquatic habitat. Table 6. Scale of Ecological Health: Colorado River Headwaters Williams Fork River Current Conditions Mainstem Williams Fork River Williams Fork River Tributaries - Current Conditions McQueary Creek Bobtail Creek Steelman Creek Jones Creek Fraser River - Current Conditions S1. Headwaters to Vasquez Creek S2. Vasquez Creek to St. Louis Creek S3. St. Louis Creek to Ranch Creek S4. Ranch Creek to Mouth of Canyon S5. Mouth of Canyon to Colorado River Fraser River Tributaries - Current Conditions St. Louis Creek West Elk Creek Cooper Creek Jim Creek Vasquez Creek North Fork Ranch Main Ranch Creek Little Vasquez Creek Dribble Creek Williams Fork River King Creek Middle Fork Ranch Creek Englewood Ranch Gravity System (i.e. Meadow, South Trail, North Trail, Hurd, Hamilton, Cabin and Little Cabin creeks) South Fork Ranch Creek Wolverine Creek Cub Creek Buck Creek Headwater tributaries to Elk Creek (i.e. West Elk, West Fork Main Elk, Main Elk, and East Elk creeks) Headwater tributaries to St. Louis Creek (i.e. West St. Louis, Short, Iron, Byers, East St. Louis, and Fool creeks) Headwater tributaries to Williams Fork River (McQueary, Jones, Bobtail, and Steelman creeks) Not past tipping point Near tipping point Past tipping point 27

15 Moffat Collection System Project Final Mitigation Plan As shown in Table 6, since many of the streams already experience altered stream ecological processes and cumulative impacts to aquatic resources from existing water diversions, the additional diversions from the Current Condition to the Full Use of the Existing System and the Moffat Project may contribute to further, incremental impacts to these aquatic communities. Denver Water will provide compensatory mitigation using a watershed approach to offset such effects of the Project through implementation of the Colorado Headwaters Mitigation Project (CHMP) Mitigation Objective The Colorado Headwaters Mitigation Project (CHMP) uses a watershed-based approach to provide rehabilitation and improvements to the natural functions of aquatic resources within the Colorado Headwater Watershed Basin (8-digit HUC ). There are two components of the CHMP in both the Fraser River and Williams Fork River subbasins. The first component includes rehabilitation of two reaches of the Williams Fork River totaling 2.08 miles. The second component includes the release of flushing flows from Denver Water s diversion structures on the Fraser River, Vasquez Creek, Ranch Creek, Cabin Creek and St. Louis Creek to maintain aquatic habitat. The goal of the CHMP is to maintain and improve the quality and quantity of aquatic resources in the Colorado River headwaters. This compensatory mitigation project will provide, where practicable, the suite of functions typically provided by the affected aquatic resources to offset Project impacts to the Colorado Headwater Watershed Basin (Impact Area) [33 C.F.R 332.3(c)(2)(i)]. The CHMP is specifically designed to provide the following aquatic resource functions: improving low flow conditions; increasing the frequency and duration of flushing flows to mobilize sediment transport; increasing aquatic habitat availability, complexity and diversity; and stabilizing stream banks and reducing erosion. Williams Fork River Basin Stream Rehabilitation The objective of this stream rehabilitation project on the Williams Fork River is to restore, through mechanical manipulation, the functionality of the aquatic habitat. Denver Water has identified two segments, above and below the reservoir, as a desirable location where general restoration goals can be achieved through mechanical manipulation of the stream (collectively, hereinafter Williams Fork Mitigation Site. ). The Williams Fork Mitigation Site includes restoration activities on a total of approximately 2.08 river miles with two distinct restoration sites (Figure 8). These two sites were selected based on the potential for ecological uplift and increased aquatic functions. Restoration activities at the upper reach (1.2 miles) and lower reach (0.88 mile) will result in improved low flow conditions, instream diversity, channel stability, and streamside vegetation. The Williams Fork Mitigation Site occurs on land owned and managed by Denver Water. The rehabilitation activities proposed at the Williams Fork Mitigation Site are designed to repair the natural/historic ecological functions to a degraded aquatic resource through the manipulation of the physical characteristics of the site, which in turn will improve the chemical and biological functions of the aquatic community. Rehabilitation results in a gain in aquatic resource function, but does not result in a gain in aquatic resource area. 28

16 Figure 8. Topographic Map of Williams Fork Mitigation Site Downstream end of lower reach Upstream end of lower reach Downstream end of upper reach Upstream end of upper reach

17 Moffat Collection System Project Final Mitigation Plan Fraser River Basin Flushing Flows The objective of the flushing flows is to provide periodic high flows that maintain the bottom substrate of streams. These flows can remove fine sediments that decrease the spawning success of species such as trout, which spawn in gravel and cobble substrates. The flushing flows were developed, in part, based on flushing recommendations in the Grand County Stream Management Plan (Tetra Tech 2010). The physical stream restoration activities in the Williams Fork River basin and flushing flow augmentation in the Fraser River basin presents a systematic approach to compensatory mitigation in accordance with the 2008 Mitigation Rule by providing mitigation in the form of Permittee-responsible restoration to offset unavoidable impacts of the Project to the aquatic resources of the Fraser and Williams Fork Rivers and their tributaries. A watershed map including the impacted areas and proposed mitigation for the Colorado Headwater Watershed Basin (8-digit HUC ) is illustrated in Figure 9. Specific Project Objectives Quantifiable objectives were established for the CHMP s Williams Fork Mitigation Site and Fraser River basin flushing flows. The goal of the stream rehabilitation at the mitigation site is to restore aquatic resource form, function and services to degraded sections of the Williams Fork River. The goal of the flushing flow releases is to directly mitigate temporal sediment accumulation in upper segments of streams below Denver Water s diversions in the Fraser River Basin. The overall goal of the CHMP will be met through the following six (6) specific objectives: 1. Flushing Flow Releases: increase stream power to transport sediment and replicate natural high flow conditions. 2. Low Flow Channel Condition: re-establish appropriate channel geometry in balance with the current flow regime to establish a defined low flow thalweg. 3. Habitat and Bed Form Diversity: increase aquatic habitat and bedform diversity by establishing natural riffle/pool complexes based on typical, natural sequencing. 4. Habitat and Bed Form Diversity: increase aquatic habitat and bedform diversity by improving pool condition and instream cover. 5. Habitat and Bed Form Diversity: improve pool quality. 6. Riparian Vegetation: increase riparian vegetation adjacent to the channel to provide overhead cover, shading and reduce sediment loading to the stream. Target Stream Function Uplift Similar to Denver Water s East Slope compensatory mitigation project on South Boulder Creek described above in Section 1.2.2, the Stream Functions Pyramid Framework (Framework) will be applied for the CHMP to determine the function of existing parameters that are impaired or non-existent, which will then be compared to the functionality resulting from the mitigation activities with the goal of achieving an ecologically functioning stream segment. Per the

18 Moffat Collection System Project Final Mitigation Plan Mitigation Rule, compensatory mitigation must result in a net increase in aquatic function and services. It is the intent with this Framework that specific functional parameters can be defined, quantified and used in comparing pre- and post-project condition to ensure that the CHMP results in a functional stream system. Table 7 provides a summary of the Framework Level Category and function parameters as they relate to the CHMP. Functional parameters identified with a bullet are generally considered critical for this type of restoration project. These parameters represent critical stream and aquatic functions that can be reasonably measured, provide quantifiable results and that can be directly correlated to performance standards. While these functional parameters have been selected for the CHMP it should be noted that in the Framework these higher-level categories (Levels 1, 2, and 3) correlate to many other lower level (Level 4 and 5) categories and functions that have not been specifically addressed. Table 8 provides a summary of the Mitigation Objectives as they relate to target stream functions. Table 7. Summary of Level, Category and Function Parameters Selected for the CHMP Level-Category Function Parameter Description Level 1-Hydrology Increased High Flows (Flushing Flows) Level 2-Hydraulics Flow Depth Level 3-Geomorphology Bed Form Diversity Pool Quality Riparian Vegetation Buffer Density Level 4-Physicochemical No direct alterations to the system physicochemical proposed. Level 5-Biology Indirect benefits of Levels 1, 2 and 3. Aquatic Life (fish and macroinvertebrate communities) (Habitat Availability) 30

19 Moffat Collection System Project Final Mitigation Plan Table 8. Mitigation Objectives and Target Functions of the CHMP Specific Mitigation Objective Functional Category - Functional Parameter* Functional Description* 1 Increased High Flows (Flushing Flows) 2 Low flow channel improvement - establish defined thalweg 3 Habitat and bedform diversity increase riffle/pool complexes 4 Habitat and bedform diversity - improve pool condition and instream cover 5 Habitat and bedform diversity improve pool quality 6 Riparian vegetation - increase density of riparian vegetation along stream corridor Level 1 Hydrology Flushing Flows Level 2 Hydraulics Flow Depth Level 3 Geomorphology Bedform Diversity Level 3 Geomorphology Bedform Diversity Level 3 Geomorphology Bedform Diversity/Pool Quality Level 3 Geomorphology Buffer Density Flushing flows remove sands and fine gravels, maintain channel geometry and improve aquatic habitat. Improvement to this Level 1 function has beneficial effects on all other levels of the Framework. Transport of water in the channel, on the floodplain and through sediments. It defines how water behaves once it reaches a channel and how it interacts with the bed, banks, floodplain, hyporheic zone, etc. Level 2 functions have a dramatic effect on Level 3 (geomorphology) and affect many functions in Levels 4 and 5 because they determine the amount of force and power that is exerted by the water on aquatic habitats. Transport of wood and sediment to create diverse bed forms and dynamic equilibrium. Natural streams rarely have flat uniform beds. Instead, the hydraulic and sediment transport processes shape the stream bed into a myriad of forms, slopes and type of bed materials. Geomorphic functions create diverse bed forms and channel stability (dynamic equilibrium) that has a dramatic effect on Level 4 and 5 functions. Riparian buffers or zones are the vegetated regions adjacent to streams that are critical to providing channel stability, cover/shade, wood recruitment to the channel, and a source of carbon. Restoration of riparian vegetation provides the vegetative structure to support many of the Level 3, 4, and 5 functions. Note: *Based on A Function-Based Framework for Stream Assessments and Restoration Projects (Harman et al. 2012) Site Selection Site selection for potential mitigation opportunities followed a watershed approach by taking a landscape view of the Colorado Headwater Watershed Basin (Impact Area), how it functions, and its need for improvement. The 2008 Mitigation Rule emphasizes the strategic selection of mitigation sites on a watershed basis and the desire to maintain and improve the quantity and quality of other aquatic resources. The following framework per the 2008 Mitigation Rule was implemented as part of the site selection process: 31

20 Moffat Collection System Project Final Mitigation Plan 1. No mitigation banks or in-lieu fee program currently service the Fraser and Williams Fork River watersheds that could provide appropriate stream mitigation credit; therefore, Permittee-responsible mitigation was determined most appropriate. 2. Locations for compensatory mitigation options were focused within the same watershed as the Impact Area and at locations where the replacement of functions and services is most likely to be successful. 3. Rehabilitation and flushing flow releases were determined to be the preferred method of compensatory mitigation for the incremental effects to stream habitat. Restoration of existing degraded stream reaches in the Williams Fork River basin was considered the most appropriate option as the likelihood of success is greater when compared to establishment, and the potential gains in terms of aquatic resource functions are greater when compared to enhancement or preservation. In addition to restoration, since impacts are related to flow depletions, flushing flow releases on five streams in the Fraser River basin were considered to be an appropriate option to enhance flow regimes to support stream health and aquatic habitats. 4. Onsite and in-kind mitigation opportunities were considered first. Flushing flows and restoration will be provided within the impacted watershed. Segments of the Fraser and Williams Fork Rivers, their tributaries and other tributaries to the Colorado River were evaluated for potential restoration efforts that could present an uplift to functions and services while achieving adequate mitigation where long-term protections could be provided. Few segments were identified that exhibited restoration potential. 5. Opportunities for a rehabilitation project on the Fraser River were evaluated. Communication with Granby Ranch identified a restoration priority reach on the Fraser River near Granby. Denver Water consulted with Granby Ranch to develop an aquatic habitat improvement project on the Fraser River including instream habitat improvements, land management for ecological benefits, and native riparian enhancements. Although this reach is considered by CPW and Granby Ranch to be a restoration priority, the ecological benefits of the restoration project would be severely limited due to the encumbrance of an adjacent Union Pacific Railroad easement, which overlaps portions of the river channel and in some areas extends across the entire width of the river channel. To avoid this easement, physical habitat restoration would be limited to certain areas and would not occur across the entire width of the channel. If the restoration project were to proceed with these restrictions, the likelihood for unintended impacts such as erosion, bank instability, and ultimately project failure would increase substantially. After examining land ownership in the Fraser River basin, Denver Water did not identify any other opportunities for stream restoration that would also meet the 2008 Mitigation Rule and the permitting timeframe. 6. Denver Water identified restoration priority reaches on the Williams Fork River in the immediate vicinity of the reservoir (Williams Fork Mitigation Site). The Williams Fork River in this area is an important aquatic resource from the perspective of both the CPW, who use the upper reach near the inlet for fish monitoring and egg harvesting, as well as the general public who use the river upstream of the dam for recreation and fishing. Denver 32

21 Moffat Collection System Project Final Mitigation Plan Water has identified these reaches, above and below the reservoir, as areas where restoration could be completed and protected. Key concerns with the existing conditions of the mitigation site include low flow conditions, instream habitat complexity, bank instability, and lack of shading. These common concerns are prevalent throughout portions of the lower Williams Fork and Fraser River basins. 7. The Williams Fork Mitigation Site is situated on land owned by Denver Water, which has conservation-oriented land practices that allow for long-term management, adaptive management and site protections. The proposed Mitigation Site will be protected through use restrictions established by a real estate instrument (i.e., conservation easement or deed restriction). 8. The CHMP provides appropriate mitigation, is located in the upper Colorado River watershed, which is the same watershed as where the Project impacts will occur, it has been identified as a priority for restoration, and it exhibits similar stream characteristics, functions and services as the impacts of the Project identified in the Final EIS. In summary, the CHMP offers the following: Watershed-based approach. The CHMP will restore a total of approximately 2.08 miles of the Williams Fork River as well as provide flushing flow releases on the Fraser River and its tributaries: Vasquez Creek, Ranch Creek, Cabin Creek, and St. Louis Creek. Holistically, this mitigation project exemplifies the watershed-based approach consistent with the 2008 Mitigation Rule. Same Hydrologic Unit Code. The CHMP is located within the same watershed HUC as the Moffat Project impacts to the Fraser and Williams Fork rivers in the Colorado Headwater Watershed Basin (8-digit HUC ). Same EPA-recognized Ecoregion. The CHMP river restoration site and flushing flows to benefit aquatic resources are located within the same ecoregion (i.e. EPAdesignated Level III Ecoregion 21- Southern Rockies) as the Moffat Project impacts to the Fraser and Williams Fork rivers (Chapman et al. 2006) Site Protection Instrument Denver Water will provide the construction, monitoring, and long-term protection for the Williams Fork Mitigation Site per the requirements of the Corps Section 404 permit. As for long-term protection of the Williams Fork Mitigation Site, the stream reaches are located on land owned and managed by Denver Water, which are above and below Williams Fork Reservoir. Denver Water is preparing a real estate instrument (conservation easement or deed restriction) that protects the natural resources and restricts activities at the site. Denver Water is legally obligated to provide the flushing flows in the Fraser River basin through its 2016 Settlement Agreement with the U.S. Forest Service. 33

22 Moffat Collection System Project Final Mitigation Plan Baseline Information The Williams Fork Mitigation Site consists of rehabilitation activities on two reaches totaling approximately 2.08 miles (10,982 linear feet; 9.3 acres) of the Williams Fork River, with one reach located upstream and one reach located downstream of the Williams Fork Reservoir (Figure 9). Restoration activities will be performed on a total of approximately 1.81 miles of the Williams Fork River, which will complement an existing high quality 0.27-mile section, to create a total of approximately 2.08 miles of high quality aquatic habitat. The upper restoration reach is 1.20 miles in length and is located immediately upstream of the Williams Fork Reservoir. The lower reach is 0.88 miles in length and starts approximately 400 feet downstream from the toe of the dam and 30 feet downstream of the USGS gage. The lower reach restoration activities include 0.23 miles of improvements at the upstream end, a section of 0.27 miles where no improvement work is recommended, followed by 0.38 miles of improvements on the downstream end extending to Denver Water s property line (Figures 10 and 11). Based on an initial review of baseline conditions, the existing physical characteristics of the stream at the Williams Fork Mitigation Site is considered Not Functioning or Functioning-at- Risk within the context of the Framework. Flushing flows will be provided at the following five streams: Fraser River Vasquez Creek Ranch Creek Cabin Creek St. Louis Creek Physical Functions of Mitigation Area The Williams Fork Mitigation Site consists of two reaches on the Williams Fork River, which are situated in the Williams Fork Subbasin (12-digit HUC ). The reaches are located at elevations ranging from approximately 7,860 to 7,550 feet. The Williams Fork River through the two reaches is a relatively large, perennial stream dominated by gravel, cobble and boulder substrate. The upper site and downstream end of the lower site are flatter gradient streams that have a riffle/pool bedform. Current conditions are dominated by long continuous riffles; pool habitat is limited. The upstream portion of the lower site is steeper and is a step/pool bedform. Based on an average slope of 0.8%, the upper reach and the downstream portion of the lower reach are classified as Type C stream segments using the Rosgen classification system, where sequencing of steeps (riffles) and flats (pools) should dominate the bedform linked to a meandering geometry. The primary morphological features of the "C" stream type are the sinuous, low relief channel, the well-developed floodplains built by the river, and characteristic "point bars" within the active channel. The channel aggradation/degradation and lateral extension processes, notably active in "C" stream types, are inherently dependent on the natural 34

23 Figure 10. Aerial Image of Williams Fork Mitigation Site

24 Figure 11. Photos and Descriptions of the Williams Fork Mitigation Site Photo 1 illustrates the upper mitigation site facing downstream. As the photo illustrates the stream is dominated by a wide riffle with minimal instream diversity. There is good riparian vegetation along the banks of the upper site, so restoration will focus on instream habitat improvements in this area.

25 Photo 2 shows the main culvert crossing in the upper mitigation site. At low flow conditions the limited amount of water spreads across the overly wide channel bank creating suboptimal aquatic habitat.

26 Photo 3 shows the upstream portion of the lower mitigation site taken from along the right bank facing north. This area is different than the upper site and the downstream portion of the lower sites in that here the river is confined within a narrow corridor and it does not access its floodplain. Improvements in this area will create step pool sequences that mimic the natural bedform of a Type B channel. Improvements will include creation of a low flow thalweg to improve habitat during times of minimal reservoir releases.

27 Photo 4 is of the lower mitigation site as flows exit the canyon section where no work is proposed. This photo was taken facing downstream. The photo shows how the stream at this location transitions from a tight canyon environment (lower left side of photo) into a more open valley. Improvements at the lower site will improve deeper water habitat by shaping the channel to provide a defined thalweg and introducing additional instream habitat.

28 Photo 5 shows the middle section of the lower mitigation site. The area will be improved by addressing low flow conditions and increasing instream habitat diversity.