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HomeMy WebLinkAboutCOUNCIL - AGENDA ITEM - 06/03/2014 - FIRST READING OF ORDINANCE NO. 090, 2014, APPROPRIAgenda Item 23 Item # 23 Page 1 AGENDA ITEM SUMMARY June 3, 2014 City Council STAFF Ken Sampley, Stormwater/Floodplain Program Mgr Ellen Switzer, Utilities Financial Operations Manager SUBJECT First Reading of Ordinance No. 090, 2014, Appropriating Unanticipated Revenue in the Stormwater Fund to Design and Construct the Fort Collins / Timnath Boxelder Creek Flood Mitigation Projects. EXECUTIVE SUMMARY The purpose of this item is to appropriate funds in the amount of $3,750,000 to design and construct the Fort Collins/Timnath Boxelder Creek Improvements, as outlined in the Sixth Amendment to the Fort Collins – Timnath Intergovernmental Agreement (IGA), as adopted by City Council under Ordinance No. 047, 2014 on April 1, 2014. STAFF RECOMMENDATION Staff recommends adoption of this Ordinance on First Reading BACKGROUND / DISCUSSION In February 2009, Fort Collins and Timnath entered into an intergovernmental agreement (IGA) regarding Growth Management Areas (GMAs) for the two communities, associated issues authorizing the disposition of certain properties, and stormwater and floodplain issues associated with Boxelder Creek and the “Boxelder Creek Overflow Project.” There have been seven (7) amendments to the IGA. The Sixth Amendment to the IGA was adopted under Ordinance No. 047, 2014 at the April 1, 2014 Regular Council Meeting. The locations of the Fort Collins / Timnath Boxelder Creek Improvements and Boxelder Basin Regional Stormwater Authority (BBRSA) Regional Stormwater Improvements are shown on Attachment 1. The Fort Collins / Timnath Boxelder Creek Improvements consist of: Lake Canal Crossing of Boxelder Creek -- A siphon and associated appurtenances to transport flows in the Lake Canal beneath Boxelder Creek just west of Interstate Highway 25. Boxelder Creek Outfall and Prospect Road Improvements -- A side spill weir (split flow channel) and flood conveyance channel on Boxelder Creek upstream of Prospect Road along with six 12’ x 4’ concrete box culverts beneath Prospect Road west of Interstate Highway 25, associated utility relocations (i.e. electric, water, wastewater, gas and telecommunications), roadway restoration, and a flood conveyance channel south of Prospect Road to the Poudre River and associated appurtenances. Boxelder Creek at Interstate Highway 25 (I-25) -- Drainageway and channel improvements and grading adjacent to and upstream (east) of I-25 and the opening of two existing blocked culverts beneath I-25. Agenda Item 23 Item # 23 Page 2 FINANCIAL / ECONOMIC IMPACTS The total cost of these projects is currently estimated to be $4,000,000. Fort Collins and Timnath have agreed to share equally in the costs to complete the projects. As outlined in the Sixth Amendment to the IGA, Fort Collins will be able to use the remaining funds ($1,750,000) placed into escrow as part of the original IGA towards its share of the project funding. Fort Collins will use existing appropriations from the Boxelder Authority project account in an amount up to $250,000 to fully fund fifty percent (50%) of the total cost of the Fort Collins/Timnath Projects. The parties agree that the escrowed funds, together with the additional Fort Collins funds, are intended as a match to payments by Timnath, or the TDA on behalf of Timnath, in the amount of $2,000,000 to complete the projects. Timnath, or the TDA on behalf of Timnath, will pay the $2,000,000 to Fort Collins who will manage the design and construction of the projects. ENVIRONMENTAL IMPACTS None of the Fort Collins / Timnath Boxelder Creek Improvements are located within a designated Fort Collins Natural Area. The reach of Boxelder Creek from the Lake Canal Crossing upstream to just east of I-25 (approximately 300 lineal feet) will be reconstructed to accommodate the opening of the two existing blocked culverts beneath I-25. The existing Lake Canal flume which extends over Boxelder Creek and is subject to failure in a flood event will be removed. The new flood conveyance channel upstream of Prospect Road will be constructed at an elevation 2-3 feet above the Boxelder Creek bed and will have minimal impact on the existing creek section. This new flood conveyance channel will extend southwesterly through new box culverts under Prospect Road and will outfall into a branch of the Poudre River downstream. No construction is anticipated within the 100-Year Poudre floodplain. The location, size and impacts of the stormwater improvements have been minimized to the extent reasonably possible and all construction activities and improvements shall be sensitive to the natural features of the affected property. Any area impacted by construction activities shall be restored to pre- construction natural conditions to the extent reasonably possible, using native vegetation. All appropriate environmental permitting including the Endangered Species Act (ESA) Clearance and USACE 404 Permit will be obtained. Council approved the Stormwater Quality Master Plan Update and associated Stream Rehabilitation Program and project priorities presented by Fort Collins Utilities Stormwater staff in mid-2012. This included analysis and a report from Colorado State University entitled “Assessments and Rehabilitation Decision Makin Framework for the Streams of Fort Collins (CSU Study) to help guide and prioritize future stream management and rehabilitation within the City. The Boxelder Creek / Cooper Slough Water Quality Master Plan Selected Plan is Attachment 2 to this memorandum. The reach of Boxelder Creek from the Lake Canal Crossing downstream to Prospect Road (identified as Reach 3-1 in the Boxelder Creek/Cooper Slough Master Plan) was identified for future stream rehabilitation and restoration improvements with a preliminary estimated cost of $780,000. It is priority number 35 within the Stream Rehabilitation program (see Attachment 3). Annual funding in the amount of $650,000 for 2013 and 2014 was approved by Council as part of the 2013-14 BFO process for stream rehabilitation and regional Best Management Practices (BMPs) projects. These funds have been allocated to the highest priority stream rehabilitation projects (Fossil Creek Reach 4-1 and Spring Creek Reach 1-5). Stream rehabilitation funding in the amount of $650,000 and $700,000 has been requested for 2015 and 2016, respectively, as part of the 2015-16 BFO process. Boxelder Creek Reach 3-1 would not typically be funded for 10-15 years given the current annual funding allocations. However, Stormwater staff is coordinating with the developer of the Interstate Land site located at the northwest corner of I-25 and Prospect Road to potentially design and construct the proposed stream rehabilitation projects in this reach over the next several years. PUBLIC OUTREACH Information on the Boxelder Basin Regional Stormwater Authority and progress on its regional projects is presented monthly at the BBRSA Board of Directors meeting which is held at 4:00 PM the fourth Wednesday Agenda Item 23 Item # 23 Page 3 of each month at the Leeper Center, 3800 Wilson Avenue, Wellington, Colorado. The Board Meeting agendas and minutes along with relevant studies, mapping and other information are available for review at the following BBRSA website hyperlink: http://www.boxelderauthority.org/. In addition, the BBRSA maintains a mailing list of parties who have expressed interest in receiving information and regularly distributes Board Meeting agendas and materials. The BBRSA also publishes and distributes a quarterly newsletter which provides information and updates on the authority and its programs. Comprehensive updates on the BBRSA were presented at the recent public meetings listed below: January 28, 2014 City Council Work Session February 26, 2014 BBRSA Board of Directors Work Session March 18, 2014 Regular City Council Meeting April 1, 2014 Regular City Council Meeting. ATTACHMENTS 1. Boxelder Creek Watershed -- Project Map (PDF) 2. Boxelder - Cooper Slough Stream Rehabilitation Selected Plan (PDF) 3. Stream Rehabilitation Program -- Priority Ranking Summary 06-03-14 (PDF) 4. PowerPoint Presentation (PDF) EAST SIDE DETENTION FACILITY (ESDF) and COUNTY ROAD 52 IMPROVEMENTS LARIMER / WELD CANAL CROSSING STRUCTURE (LWCCS) BOXELDER CREEK AT I-25 LAKE CANAL CROSSING OF BOXELDER CREEK BOXELDER CREEK OUTFALL AND PROPSECT ROAD IMPROVEMENTS BOXELDER CREEK WATERSHED -- PROJECT MAP BOXELDER CREEK/COOPER SLOUGH BASIN WATER QUALITY MASTER PLAN SELECTED PLAN Prepared for: City of Fort Collins Stormwater Department 700 Wood Street Fort Collins, CO 80521 Prepared by: Anderson Consulting Engineers, Inc. 375 E. Horsetooth Road, Bldg. 5 Fort Collins, CO 80525 (ACE Project No. COFC2012.03A) March 30, 2012 COFC2012.03A_BECS Selected Plan.docx 7-i Anderson Consulting Engineers, Inc. TABLE OF CONTENTS VII. WATER QUALITY MASTER PLAN SELECTED PLAN ......................................................................... 7-1 7.1 INTRODUCTION ................................................................................................................ 7-1 7.2 TRIPLE BOTTOM LINE (TBL) EVALUATION ........................................................................ 7-1 7.3 GENERAL RECOMMENDATIONS FROM THE CSU STUDY ................................................. 7-1 7.4 STREAM SUSCEPTIBILITY FINDINGS AND RECOMMENDATIONS ..................................... 7-5 7.5 HABITAT FINDINGS AND RECOMMENDATIONS .............................................................. 7-9 7.6 WATER QUALITY RECOMMENDATIONS ......................................................................... 7-19 7.7 SUMMARY OF COSTS ..................................................................................................... 7-19 7.8 REFERENCES ................................................................................................................... 7-20 LIST OF FIGURES Figure 7.1 Cooper Slough Basin Management Susceptibility Reaches ............................................. 7-3 Figure 7.2 Cantilever Bank Failure in Bend ....................................................................................... 7-5 Figure 7.3 Dense Willows Line the Banks throughout Reach ........................................................... 7-6 Figure 7.4 Cantilever Bank Failure in Bend ....................................................................................... 7-7 Figure 7.5 Areas without Wood Vegetation Susceptible to Undercutting ....................................... 7-8 Figure 7.6 Pockets of Dense Willows throughout Reach .................................................................. 7-9 Figure 7.7 Cantilever Bank Failure in Bend ....................................................................................... 7-9 Figure 7.8 Cooper Slough Basin Management Habitat Reaches and Grades ................................. 7-11 Figure 7.9 Weir for Gauging Station at Downstream End of Reach ............................................... 7-12 Figure 7.10 Leaking Elevated Irrigation Pipe Causing Instabilities Downstream .............................. 7-13 Figure 7.11 Looking Upstream at the Stream Next to the Visitor Center......................................... 7-13 Figure 7.12 Channel Completely Choked by Aquatic Vegetation ..................................................... 7-14 Figure 7.13 Aerial Photograph from 1999 ........................................................................................ 7-15 Figure 7.14 Possible Old Footbridge Causing Fish Passage Issues .................................................... 7-16 Figure 7.15 Dense Willows Lining the Left-Hand Side of the Bank ................................................... 7-17 Figure 7.16 Dense Willows in Many Areas of the Reach .................................................................. 7-17 Figure 7.17 Bare Riparian Area from Trampling ............................................................................... 7-18 Figure 7.18 Middle of the Reach with Upland Grasses Being Dominant .......................................... 7-19 LIST OF TABLES Table 7.1 Summary of Susceptibility Scores and Percent Bank Stability for Boxelder Creek .......... 7-9 Table 7.2 Summary of Final Grades for the Habitat Assessments for Boxelder Creek ................. 7-10 COFC2012.03A_BECS Selected Plan.docx 7-1 Anderson Consulting Engineers, Inc. VII. WATER QUALITY MASTER PLAN SELECTED PLAN 7.1 INTRODUCTION With the completion of the Conceptual Alternatives Phase for the Cooper Slough Basin, Anderson Consulting Engineers, Inc. (ACE) initiated the Selected Plan Phase. It is noted that in the Conceptual Alternatives Phase, the Boxelder Basin was not evaluated from a water quality improvement standpoint as it is under the regulation of the Boxelder Basin Stormwater Authority. Since the completion of the Conceptual Alternatives Phase, CSU has completed a stream assessment study providing both stream susceptibility and habitat recommendations for Boxelder Creek. Consequently, it is still assumed that water quality enhancement in the Boxelder Basin will be addressed with future development under the direction of the Boxelder Basin Stormwater Authority; however, this Master Plan Selected Plan does identify the CSU stream assessment findings and recommendations for Boxelder Creek. Reference is made to Sections 8.7 for a detailed discussion of the Conceptual Alternatives Phase including the following: (a) description of the major drainage corridors of the Cooper Slough Basin; (b) which of these drainage corridors were and were not evaluated for water quality enhancement and why; (c) a discussion of each of the conceptual water quality enhancement alternatives and how applicable they may be for a given drainage corridor; and (d) an evaluation decision matrix and recommended water quality enhancement alternatives for each of the major drainage corridor. 7.2 TRIPLE BOTTOM LINE (TBL) EVALUATION Following the completion of the Conceptual Alternatives Phase it was concluded by City Staff that treatment of stormwater within the Cooper Slough Basin would be addressed according to stormwater criteria imposed upon new development. In addition, it was assumed that treatment of stormwater within the Boxelder Basin would be addressed with future development under the guidance of the Boxelder Basin Stormwater Authority. As a result a TBL evaluation was not performed for either the Cooper Slough or Boxelder Basins. 7.3 GENERAL RECOMMENDATIONS FROM THE CSU STUDY In January 2012, Colorado State University researchers, on behalf of the City of Fort Collins Stormwater Division, released a report entitled “Assessments and Rehabilitation Decision Making Framework for the Streams of Fort Collins” (CSU Study) to help guide and prioritize future stream management and rehabilitation within the City. The objectives of this report were to: • Perform a geomorphic assessment on a segment-by-segment basis of the ten streams listed above to determine channel evolution stage, channel susceptibility to vertical and lateral erosion, and stream habitat condition. COFC2012.03A_BECS Selected Plan.docx 7-2 Anderson Consulting Engineers, Inc. • Use the resulting data to identify geomorphic thresholds that sustain meandering channels and other heterogeneous physical habitats and use this information to assess candidate restoration sites by determining if the local geomorphic controls are compatible with sustaining sinuosity and habitat diversity. • Identify and prioritize future stream management and rehabilitation work through the development of a Multi-Criterion Decision Analysis (MCDA) matrix that can be used to select projects that simultaneously improve habitat, reduce susceptibility, and provide the geomorphic conditions that sustain diverse and stable channels. Stream assessments were carried out between June and October 2011. As part of this report, Boxelder Creek was evaluated for its susceptibility to erosion and the quality of its habitat. It was broken into reaches as illustrated on Figure 7.1. General findings related to channel susceptibility in the City of Fort Collins include: • By far, the most pervasive source of channel instability in the surveyed streams is bank failure induced by amplified durations of moderate flows. Urbanization, irrigation flows, and stormwater best management practices (BMPs) that do not control the full spectrum of erosive flows contribute to this response. The cumulative effects of increased durations of erosive flows on the toes of bank result in widespread undercutting and cantilever failure. • Stream reaches were assessed for both lateral and vertical susceptibility to erosion and assigned to Low, Medium, and High risk categories. Results show that the majority of the streams in Fort Collins have incised down to erosion-resistant materials including bedrock, hardpan, claypan, or a coarse armor layer. Due to the more erodible bank material and presence of upland grasses, which provide less root reinforcement for bank stabilization than riparian plant species, the majority of streams are at a higher risk of lateral erosion and future widening. This is evidenced by the undercutting and resulting cantilever failures that are occurring throughout the City. General findings related to channel habitat in the City of Fort Collins include: • In several locations, physical habitat has improved since the Zuellig (2001) surveys; however, there remain widespread opportunities for habitat improvement. In most instances, habitat has improved due to land-use change and the reestablishment of riparian vegetation. In other cases, the timing of when the habitat assessments were conducted have shown that seasonality can greatly affect habitat parameters such as embeddedness, frequency of riffles, and epifaunal substrate / available cover. • Resulting reach grades from the habitat assessments are as follows: 21% were rated B, 42% were rated C, 26% were rated D, and 11% were rated E. The most limiting factors were aquatic habitat diversity, riparian vegetation and width, and connectivity. COFC2012.03A_BECS Selected Plan.docx 7-3 Anderson Consulting Engineers, Inc. BOXELDER BASIN SLOUGH SUBBASIN NO. 8 DITCH SUBBASIN CLPRID SUBBASIN PROSPECT SUBBASIN NO. 8 DITCH SUBBASIN C & S RAILROAD SUBBASIN ANHEUSER-BUSCH SUBBASIN COOPER SLOUGH BASIN MANAGEMENT SUSCEPTIBILITY REACHES Drake Rd Prospect St Mulberry St 14 I 25 Timberline Rd Lemay Ave Edora Park Parkwood Lake Lemay Ave Deadman Lake Reach 1-1 Reach 1-2 Lake Sherwood Timnath Reservoir Timberline Rd I 25 14 Vine Dr Reach 1-3 Reach 1-4 Reach 3-1 Reach 3-2 Reach 4-1 Reach 5-1 Reach 5-2 Reach 5-3 Reach 6-1 Reach 6-2 Reach 6-3 Legend Susceptibility Reach Break Box Elder Creek Cooper Slough Subbasins 02,1,250 5005,000 Feet Susceptibility Risk Creek Reach Mass Wasting Fluvial Erosion Stable Vertical Lateral Boxelder Creek 1-1 1% 75% 24% Low Medium 1-2 2% 78% 20% Low Medium 1-3 1% 49% 50% Low Low 1-4 1% 89% 10% Low Medium 3-1 5% 80% 15% Medium Medium 3-2 5% 95% 0% Medium Medium COFC2012.03A_BECS Selected Plan.docx 7-4 Anderson Consulting Engineers, Inc. • Grade control structures are widespread throughout Fort Collins and have for the most part successfully stopped erosion and further stream degradation. However, grade control in most instances has also negatively influenced aquatic ecosystems by decreasing habitat diversity through the creation of glide habitat. Furthermore, some grade control structures are impassable by fish and have disrupted longitudinal connectivity within the streams. Opportunities for modifying existing grade controls to simultaneously correct connectivity issues, while supporting the geomorphic characteristics associated with sinuosity and habitat diversity exist in some locations, especially where structures are vulnerable to flanking and instability. • The greatest benefits to stream habitat in Fort Collins would come from modifying selected grade control structures to transform straight glides to more sinuous and diverse habitats, while also allowing fish passage. Smaller-scale habitat improvements such as restricting mowing and planting riparian/wetland species such as willows, rushes, and sedges, can be both cost effective through the use of volunteers, and greatly benefit stream habitat by improving water quality and bank stability. • There are areas in Fort Collins that currently have functional and diverse habitat and the importance of protecting these areas from future land-use changes should be a critical element of future stream management. If surrounding land cannot be protected through purchase or easement, ensuring that the streams have sufficient riparian buffers and that stormwater infrastructure for new developments addresses the full-spectrum of flows would help maintain existing habitats of higher quality. The recommendations from the CSU Study were separated into “large” and “small” stream categories, based on the two-year discharges. For the purposes of this study, Boxelder Creek is considered to be a small stream. This stratification was necessary because glide habitats tend to have significantly higher unit stream power. Using the large streams to set a unit stream power for a small stream could potentially result in overestimation and an unstable level of energy. The CSU Study also found that general geomorphologic recommendations for streams with functional meandering planforms include: • Sinuosities between 1.2 and 1.7; • Slopes of approximately 0.22% - 0.45%; • For small streams, unit stream power from 25-62 W/m2 (but generally 30-35 W/m2 in order to eliminate glide sections); • For large streams, unit stream power greater than 75 W/m2; and • Width-to-depth ratios from 3.2-5.3. COFC2012.03A_BECS Selected Plan.docx 7-5 Anderson Consulting Engineers, Inc. Figure 7.2 Cantilever Bank Failure in Bend. Of course, all of these parameters are closely interrelated, and combine to form a delicate balance wherein a stream is functional and stable. One parameter cannot be changed in isolation, as it could upset the balance, leading to channel instabilities. Additionally, general recommendations for habitat improvement for small streams include: • Minimizing glide sections, which can cause aggradation (which can destroy habitat); • Frequent riffle/pool sequencing; • 100’ stream buffer (50’ each side); and • More wetland and riparian vegetation. 7.4 STREAM SUSCEPTIBILITY FINDINGS AND RECOMMENDATIONS The CSU Study only evaluated stream susceptibility for Boxelder Creek, within the Boxelder Basin. No streams were evaluated by CSU in the Cooper Slough Basin. Consequently, this section only applies to the Boxelder Creek and is taken from the CSU Study. Overall, Boxelder Creek is one of the City’s streams that is least affected by urbanization; however, its flow regime is highly altered due to numerous canals that divert and augment streamflows at various locations. Nevertheless, it may be relatively susceptible to future degradation due to the potential encroachment of urban land use as described in the reach descriptions below. Each individual reach was determined to be at Low, Medium, or High risk for lateral and vertical erosion. It is important to stress that in determining the overall risk for incision or widening they can be linked together. When determining at what risk a channel is for vertical erosion not only is the presence of a non-erodible layer important, but also the depth to that layer. If the average depth is beyond the critical bank height for the channel then failures are expected to occur, followed by channel widening. Table 7.1 is presented to provide the percent of each reach that had fluvial erosion, mass wasting, or was stable. The level of risk to vertical and lateral erosion is also shown. Although the assessments were thorough, before any future stream rehabilitation work is performed it is essential that the susceptibility risk be updated and the erodibility of any coarse layers, hardpan, or claypan be determined, especially if found at a depth below the bed surface to protect against future instabilities. Findings are described on a reach-by-reach basis below. The susceptibility reaches are illustrated on Figure 7.1. Boxelder Creek, Reach 1-1 Reach 1-1 is located in the Poudre River floodplain and as a result there is a coarse cobble layer present 0.5 to 2 feet below the bed surface which extends out underneath the banks. Toe erosion and undercutting are occurring directly above the cobble layer, and have resulted in cantilever failures in some bends (Figure 7.2). If the undercutting worsens, more bank failures and resulting widening COFC2012.03A_BECS Selected Plan.docx 7-6 Anderson Consulting Engineers, Inc. Figure 7.3 Dense Willows Line the Banks throughout Reach. could occur. Cattails and smooth Brome grass are dense within this reach, but do not provide significant root reinforcement, as evidenced by the prominent undercutting. Overall, the channel appears to be more susceptible laterally than vertically. No stream susceptibility recommendations were identified by CSU for this reach. Table 7.1 – Summary of Susceptibility Scores and Percent Bank Stability for Boxelder Creek. Creek Reach Mass Fluvial Wasting Erosion Stable Susceptibility Risk Vertical Lateral Boxelder Creek 1-1 1-2 1-3 1-4 3-1 3-2 3-3 4-1 5-1 5-2 5-3 6-1 6-2 6-3 1% 75% 24% 2% 78% 20% 1% 49% 50% 1% 89% 10% 5% 80% 15% 5% 95% 0% --- --- --- 0% 100% 0% 1% 99% 0% 1% 99% 0% 0% 50% 50% 1% 99% 0% 25% 75% 0% 25% 75% 0% Low Medium Low Medium Low Low Low Medium Medium Medium Medium Medium --- --- Low Medium Low Low Low Medium Low Low Low Medium Low Low Low Medium Boxelder Creek, Reach 1-2 This reach is also within the Poudre River floodplain and is vertically controlled by a coarse cobble layer 0 to 1.5 feet below the bed surface and cantilever failures are present in a couple of the bends. There is little to no woody vegetation within the reach, and areas with prominent undercutting could be susceptible to future widening. Of concern is a reach downstream of a leaking elevated irrigation pipe that crosses the stream. Within this reach bank failures are evident in every bend, which COFC2012.03A_BECS Selected Plan.docx 7-7 Anderson Consulting Engineers, Inc. Figure 7.4 Cantilever Bank Failure in Bend. to lateral erosion in areas without woody vegetation and incision would stop at the cobble layer. In areas where the cobble layer is deeper, vertical erosion could ultimately result in banks being higher than critical bank height, which would result in failure. No stream susceptibility recommendations were identified by CSU for this reach. Boxelder Creek, Reach 1-4 In Reach 1-4 cantilever failures are limited to a couple of bends, with undercutting being severe in most other bends and runs. Downstream of a drop structure in the middle of the reach is a coarse layer of stream material 0.5 to 2 feet below the bed surface. Upstream of the grade control the cobble layer is buried 2 to 3 feet below the deposition material. Cattails and Brome grass are dense throughout the reach, but will not stop the severe undercutting occurring at the toe of the banks above the coarse layer. Despite the grade control created by the bridge culvert at the downstream end, and the drop structure in the middle of the reach, fluvial erosion is present throughout most of the reach. Further widening could occur if toe erosion persists. No stream susceptibility recommendations were identified by CSU for this reach. Boxelder Creek, Reach 3-1 In Reach 3-1 there is a coarse layer located from 1 foot to greater than 4 feet below the bed surface in the downstream section of the reach. Cantilever failures are present only in some of the bends (Figure 7.4). The bed is progressively depositional in the downstream direction as evidenced by the fine veneer of sediment. Runoff from agricultural fields is directly adding fine sediment into the reach, which could be alleviated by installing erosional BMPs in the fields. The bed is readily penetrable by a tile probe and the stream is susceptible to incision of at least 4 feet in some areas. The upstream quarter of the reach has a coarse layer of bed material from 0 to 2 feet below the surface. All vegetation is upland grasses which do provide some bank stability, but not as much as other riparian plant species. Overall, the reach is at Medium risk both laterally and vertically, which is significant since land use in the area could change causing future degradation within the reach. Boxelder Creek, Reach 3-2 In Reach 3-2 there was a coarse gravel layer 1 to 2 feet below a layer of fine depositional material. Cantilever failures were present in a few bends with undercutting being prominent in the rest. It is not known how much resistance to erosion the coarse layer of gravel will provide. However, assuming the coarse layer does provide resistance, the stream could be susceptible to incision down to the coarse layer and then lateral erosion as the banks mostly consist of upland grasses with prominent COFC2012.03A_BECS Selected Plan.docx 7-8 Anderson Consulting Engineers, Inc. Figure 7.5 Areas without Wood Vegetation Susceptible to Undercutting. undercutting throughout. A second field visit saw an increase in canal return flows at the upstream end of the reach, which appeared to have flushed the deep layer of fine veneer from the coarser layer. In general, flow regime is directly affected by irrigation canals. Consequently, future changes in the operation of these canals could cause channel widening and/or incision depending on the resistance of the bed material. No stream susceptibility recommendations were identified by CSU for this reach. Boxelder Creek, Reach 4-1 Reach 4-1 exhibits a coarse layer of bed material 2 to 3 feet below the bed surface in the downstream section; while the upstream section of the reach exhibits possible hardpan or coarse layer 1 to 3 feet below the bed surface. In addition, the entire reach is experiencing moderate undercutting. Although woody vegetation is present along this reach, areas without woody vegetation are susceptible to channel widening (Figure 7.5). Areas where the coarse layer is deeper, channel incision could ultimately result in bank failures. Overall, the reach is at a Medium risk to widening due to the prominent undercutting. No stream susceptibility recommendations were identified by CSU for this reach. Boxelder Creek, Reach 5-1 In Reach 5-1 a cantilever failure was identified in a single bend, and only slight undercutting is evident throughout the reach. A coarse layer of unknown resistance to erodibility is present in different areas, from 1 to 3 feet below the bed surface. Willows line the left side of the stream, but the right is dominated by upland grasses. The stream is not susceptible as long as the undercutting does not worsen on the right side where no woody vegetation is present. Boxelder Creek, Reach 5-2 In Reach 5-2 a cantilever failure was identified in a single bend, and moderate to severe undercutting is evident throughout the reach. A coarse or resistive bed material layer is present 2 to 3 feet below the bed surface. Further incision could occur down to that layer, which would ultimately result in more bank failures. With the banks only being protected by upland grasses, the moderate to severe undercutting could worsen and cause future bank failures. No stream susceptibility recommendations were identified by CSU for this reach. Boxelder Creek, Reach 5-3 In Reach 5-3 a coarse or resistive layer is present 1 to 3 feet below the bed surface. The thalweg has been scoured to the coarse layer, but both sides of the channel consist of a deep layer of fines. COFC2012.03A_BECS Selected Plan.docx 7-9 Anderson Consulting Engineers, Inc. Figure 7.6 Pockets of Dense Willows throughout Reach. Figure 7.7 Cantilever Bank Failure in Bend. Willows and cattails are dense throughout most of the reach (Figure 7.6). Areas with woody vegetation are less at risk for lateral erosion, while areas with cattails or no woody vegetation are more susceptible. The channel is at a Low risk for incision, but the erodibility of the coarse or resistive layer should be better determined if any rehabilitation work is considered. Boxelder Creek, Reach 6-1 In Reach 6-1 hardpan is 0 to 1 foot below the bed surface throughout, but is less prevalent in the upstream end. Much of the reach is used as pasture for horses resulting in several areas of trampled and bare banks. The reach would be a stable sinuous section if the horses were fenced off. Because of the trampling and hardpan, lateral erosion is more likely, especially in the heavy traffic areas with bare banks. Boxelder Creek, Reach 6-2 Throughout Reach 6-2 hardpan and bedrock are 0 to 1 foot below the bed surface and is also prominent in banks. Despite most bends being over critical height, future incision and widening is unlikely due to the hardpan presence. Seepage is prominent in many areas on the left side of the channel due to the nearby canal, which is higher in elevation. The seepage is not likely to create more instabilities as the bedrock and hardpan are keeping banks stable. Boxelder Creek, Reach 6-3 In Reach 6-3 cantilever failures are limited to bends, and undercutting is moderate throughout (Figure 7.7). A hardpan layer is located 1 foot below the bed surface in the downstream part of the reach, and 1 to 2 feet below the bed surface upstream. The banks are dominated by upland grasses, so there is less protection from erosion than if riparian plant species were present. With the presence of a hardpan, the stream is only susceptible to about another foot of incision, with subsequent widening being likely. 7.5 HABITAT FINDINGS AND RECOMMENDATIONS The CSU Study only evaluated habitat for Boxelder Creek, within the Boxelder Basin. No streams were evaluated by CSU in the Cooper Slough Basin. Consequently, this section only applies to the Boxelder Creek and is taken from the CSU Study. Boxelder Creek is the only stream that still runs directly into the Poudre River, and preserving this connectivity would maintain habitat for fish to COFC2012.03A_BECS Selected Plan.docx 7-10 Anderson Consulting Engineers, Inc. move up into Boxelder Creek to inhabit and spawn. It is also one of the least urbanized watersheds making it susceptible to future land-use changes. Final grades for the habitat assessments are provided in Table 7.2 for each reach and illustrated on Figure 7.8. Overall grades for the reaches are also presented along with grades for the three habitat categories to better distinguish which area of habitat could use the most improvement. The comparison of grades for just the parameters assessed by Zuellig (2001) are also presented. Resulting grades for the Zuellig parameters only were for the majority higher than the grades assigned by Zuellig. Table 7.2 – Summary of Final Grades for the Habitat Assessments for Boxelder Creek. Creek Reach Overall Grade Riparian Channel Aquatic Area Alterations Habitat Zuellig Parameters Only Zuellig Score Our Score Boxelder Creek 1-1 1-2 1-3 1-4 3-1 3-2 3-3 4-1 5-1 5-2 5-3 6-1 6-2 6-3 B B B --- C B D B --- C C D B B B C B C A A B D B --- --- --- C B C A D C C C E A A B --- --- --- B B C C A D E B D A A C B B C B A B A COFC2012.03A_BECS Selected Plan.docx 7-11 Anderson Consulting Engineers, Inc. BOXELDER BASIN SLOUGH SUBBASIN NO. 8 DITCH SUBBASIN CLPRID SUBBASIN PROSPECT SUBBASIN NO. 8 DITCH SUBBASIN C & S RAILROAD SUBBASIN ANHEUSER-BUSCH SUBBASIN COOPER SLOUGH BASIN MANAGEMENT HABITAT REACHES AND GRADES Drake Rd Prospect St Mulberry St 14 I 25 Timberline Rd Lemay Ave Edora Park Parkwood Lake Lemay Ave Deadman Lake Reach 1-1 Reach 1-2 Lake Sherwood Timnath Reservoir Timberline Rd I 25 14 Vine Dr Reach 1-3 Reach 1-4 Reach 3-1 Reach 3-2 Reach 4-1 Reach 5-1 Reach 5-2 Reach 5-3 Reach 6-1 Reach 6-2 Reach 6-3 0 1,250 2,500 5,000 Feet Legend Habitat Reach Break Connectivity Habitat Grades B C D E Cooper Slough Subbasins Creek Reach Overall Grade Riparian Area Channel Alterations Aquatic COFC2012.03A_BECS Selected Plan.docx 7-12 Anderson Consulting Engineers, Inc. Figure 7.9 Weir for Gauging Station at Downstream End of Reach. August to the beginning of October after spring rains and added irrigation flows have been flushing the system. It is plausible that the streams at the time of Zuellig’s study were more embedded which could also cover riffles making scores for these two parameters lower. Both riffles and embeddedness are part of the epifaunal substrate / available cover parameter, so this as well would score lower. Seasonality can influence the habitat score of a stream and this why a more indepth habitat assessment was conducted that would dampen these effects. Boxelder Creek, Reach 1-1 The most downstream section of Boxelder Creek where it enters the Poudre River was not graded for habitat due to restricted access by the Boxelder Sanitation District. It would be important to revisit this stretch to ensure no connectivity issues with the Poudre River exist. The rest of the reach can be characterized as a relatively straight channel, sinuosity of 1.1, running through a wide riparian area dominated by Brome grass and cattails. The riparian area was greater than 50-ft wide on each side of the channel and overhanging vegetation provided shade and protection for aquatic species. At the downstream end of the reach, Boxelder Creek runs into the Poudre River. Despite possible fish passage issues at the weir for the gauging station (Figure 7.9), the greatest numbers and variety of fish species were seen in this reach and reaches upstream. This shows the importance of connectivity, especially to the Poudre River. Aquatic habitat diversity was diverse with pool-riffle sequencing, and greater than 50% favorable habitat for fish. Overall, this reach ranked 5th for habitat and it is vital to ensure future degradation does not occur that could adversely affect the habitat. As the only reach in all of Fort Collins that is directly connected to the Poudre River, it is an important tributary for species to use for spawning. It appears that the weir downstream is passable by fish based purely on the number of fish seen upstream; however, it is important that under all flows fish are able to move up from the Poudre River to spawn or inhabit Boxelder Creek. As for future habitat potential, the stream should be protected from future land-use changes within and upstream of the reach. Urbanization is approaching the Boxelder Creek watershed and could have repercussions to the stability and habitat of the channel. To protect from land-use change, the stream would benefit from a wide buffer from new development and any stormwater catchments could be built with multiple orifice openings to minimize erosion potential and sustain habitat. Other work that could benefit habitat is to plant wetland/riparian plants such as willows, sedges, and rushes along the banks to help protect against possible future degradation. The existing Brome grass and cattails do not stabilize the banks as well as the other plant species would. Zuellig scored the reach a B, while this study scored it an A (Table 7.2). The biggest differences were Zuellig had lower scores for vegetative width, frequency of riffles, and embeddedness. No site description was found, so it is hard to draw conclusions, but it is possible that these parameters have improved since the Zuellig study was conducted from 1999 to 2000. COFC2012.03A_BECS Selected Plan.docx 7-13 Anderson Consulting Engineers, Inc. Figure 7.10 Leaking Elevated Irrigation Pipe Causing Instabilities Downstream. Figure 7.11 Looking Upstream at the Stream Next to the Visitor Center. Boxelder Creek, Reach 1-2 This reach was also a relatively straight channel, sinuosity of 1.1, running through a wide riparian area dominated by Brome grass with no wetland species present. The riparian area was greater than 50-ft wide on each side of the channel and overhanging vegetation provided shade and protection for aquatic species. Flow regime within the reach was slightly affected by a large outflow pipe draining irrigation from agricultural fields nearby. Aquatic habitat diversity was extremely diverse with pool-riffle sequencing and woody debris creating greater than 50% favorable habitat for fish. Overall, the reach ranked highest for total and aquatic habitat diversity, as was evidenced by the large number of fish seen. Future habitat potential should be focused on protecting the stream from land-use changes by ensuring a wide buffer and managing new development to reduce the impact of urbanization on the flow regime. The right side of the reach is a designated natural area, but the left side and farther upstream above Prospect Road the land is open for development. The only area that hurt the stream’s scores was that the riparian vegetation was all Brome grass. Placing wetland/riparian plants such as willows, sedges, and rushes along the banks will help bolster habitat and protect from possible future instabilities. One other area of concern is a leaking elevated irrigation pipe at the upstream of the reach that is adding flow and causing bank failures directly downstream (Figure 7.10). The pipe should be replaced to stop increased sediment from failed banks destroying habitat downstream. Zuellig scored the reach a B, while this study scored it an A (Table 7.2). The biggest differences were Zuellig had lower scores for vegetative width, frequency of riffles, and embeddedness. Again, since no site description was found it is hard to draw conclusions, but it is possible that these parameters have improved since the Zuellig study was conducted. Boxelder Creek, Reach 1-3 This reach was also a relatively straight channel, sinuosity of 1.1, running through a wide riparian area that consisted of upland grasses and willow shrubs and trees. Cattails were prevalent upstream of the bridge crossing to the Visitors Center, as the channel here is more altered than downstream (Figure 7.11). The riparian area was greater than 50-feet wide on each side of the channel and overhanging vegetation provided shade and protection for aquatic species. The flow regime within the reach was slightly affected by gutter outflow pipes. There was a large drop structure by the Visitors Center that prevented fish passage, which was evidenced by the steep drop in fish numbers directly upstream of the grade control (Figure 5.10). Aquatic habitat diversity was diverse with pool-riffle sequencing and greater than 50% favorable habitat for fish. Overall, the reach ranked 4th for total habitat and 2nd for COFC2012.03A_BECS Selected Plan.docx 7-14 Anderson Consulting Engineers, Inc. Figure 7.12 Channel Completely Choked by Aquatic Vegetation. aquatic habitat diversity, as was evidenced by the large number of fish seen. Habitat can be improved by retrofitting the grade control with fish passable structures and replacing the cattails in the upstream section with wetland/riparian plants such as willows, sedges, and rushes. Using fish passable structures will open a large stretch of Boxelder Creek upstream for fish to move up from the Poudre River. Zuellig scored the reach a B, while this study scored it an A (Table 7.2). The biggest differences were Zuellig had lower scores for vegetative width, frequency of riffles, and embeddedness. Again, since no site description was found it is hard to draw conclusions, but it is possible that these parameters have improved since the Zuellig study was conducted. Boxelder Creek, Reach 3-1 This reach was also considered a relatively straight channel, sinuosity of 1.3, and ran through a wide riparian area dominated by upland grasses. There was some pool-riffle sequencing, but fish habitat was marginal. Overall, the channel was considerably wider and shallower than the downstream reaches and was consequently not well-shaded by the grasses. Crop fields bordered the stream on the right side of the channel and runoff from the fields was directly adding sediment to the stream. This sediment input directly degraded the downstream section of the reach where a deep fine veneer was deposited upstream of an old farm bridge that creates a backwater. Upstream from where the crop field runoff was entering the stream, the fine veneer was drastically less. Later in the summer, a second visit to the stream showed no sediment input from the crop fields was occurring; however, aquatic vegetation was choking the channel and can be seen as a sign that flows within the stream are not enough to keep the vegetation from completely covering the channel (Figure 7.12). There was also more fine veneer present than on the previous visit, which can also be a sign of insignificant flows. Upstream from this reach, two canals are releasing water into the stream at various times and amounts. Farther upstream the channel itself is drained into a canal except for a tiny amount of flow, which is diverted into the natural channel. It can be assumed that during times of irrigation more flow is diverted into the upstream canal and less water is being delivered by the downstream canals, which in turn has lead to flows incapable of flushing the system and keeping the aquatic vegetation at bay. It is vital that flows within the channel are sufficient to keep the riffles clean and the aquatic vegetation down during the summer months to improve the habitat in the reach. If the flow regime cannot be fixed, areas that were wide and shallow could benefit from a narrower low-flow channel which would help increase velocities. Wetland/riparian plants such as willows, sedges, and rushes should also be planted along the banks to help shade the stream and protect the banks. Zuellig scored the reach a C, while this study scored it an A (Table 7.2). The main differences were Zuellig had lower scores for vegetative width, frequency of riffles, and embeddedness. The site was described as having no riffles and rating low in riparian vegetation and fish habitat. Riffles were definitely present when this study was conducted, but seeing how drastically different the channel looked upon the visits, it may be possible that when Zuellig saw the reach there had been no flushing COFC2012.03A_BECS Selected Plan.docx 7-15 Anderson Consulting Engineers, Inc. Figure 7.13 Aerial Photograph from 1999. flows, and the channel could have been completely embedded with fine veneer. It is obvious that the flow regime is what is keeping the habitat degraded at certain times, and if addressed the reach could contain some important fish habitat; especially if the impassable drop structure downstream is removed. As for the riparian vegetation, an aerial photograph from 1999 shows the area was much more impacted by agriculture and it appears that the vegetation has had time to grow back and increase its cover. With an overall grade of C for Reach 3-1 (Table 7.2), this reach has been identified for stream restoration. Assuming a cost of $300 per linear foot (provided by the City of Fort Collins), it would cost approximately $780,000 to restore this reach. Boxelder Creek, Reach 3-2 This reach was considered a relatively straight channel, sinuosity of 1.3, and ran through a wide riparian area consisting of willows, cattails, and upland grasses. There was some pool- riffle sequencing in the 200 feet downstream from a large canal outflow, but otherwise less so. As discussed in the previous section, the canal affects the flow regime in the channel and perhaps at certain times enough flow is entering from the canal to allow for the stream to form some pool- riffle sequencing. Fish habitat was rated as suboptimal for the reach overall, but better just downstream from the canal input. Upstream from the canal input, the channel is lined with riprap and vegetation consists mainly of cattails. To improve habitat the flow regime needs to be addressed as discussed for the previous reach, and wetland/riparian plants such as willows, sedges, and rushes could be planted in place of the cattails upstream of the canal. Zuellig scored the reach a C, while this study scored it an A (Table 7.2). The biggest differences were Zuel4lig had lower scores for vegetative width, frequency of riffles, and embeddedness. The site was described as having no riffles and rated low in riparian vegetation and fish habitat. Pool-riffle sequencing was occurring downstream of the canal input when this study was conducted. As mentioned before, it is possible that with such an affected flow regime Zuellig may have seen the stream at a time when flows were making the stream appear more marginal. Also, looking at an aerial photograph from 1999 (Figure 7.13), it appears that the canal input at that time may have actually been diverted into an elevated pipe and crossed the stream instead of draining into it. It is hard to tell, but if this were the case than it appears the flows from the canal have helped the habitat improve, but it could still use a better flow regime. Boxelder Creek, Reach 3-3 This reach was considered a meandering channel with a sinuosity of 1.7. The surrounding riparian area was an abandoned agricultural field with old structures for livestock. Vegetation consisted of upland grasses with the occasional willow or Russian Olive. At the upstream end an elevated canal COFC2012.03A_BECS Selected Plan.docx 7-16 Anderson Consulting Engineers, Inc. Figure 7.14 Possible Old Footbridge Causing Fish Passage Issues. crosses the stream and can add flow to the channel at times. It is this canal crossing that seems to control the flow regime and resulting habitat downstream. On two visits to the reach, the channel had substantial water in it, but was mainly one long glide. The result was a fine veneer of 2 feet deposited throughout the channel with aquatic plants covering the channel in areas. The habitat scores thus reflected the glide nature of the channel with poor habitat diversity and habitat for fish. A brief third visit back to the reach a month later, showed more water entering from the canal, and the fine veneer and aquatic plants had been flushed from the channel revealing pool-riffle sequencing in the reach. A second habitat assessment was not performed, as it was judged more important to show the degraded habitat, and how it could be improved by simply fixing the flow regime to ensure flushing flows of the fine sediment buildup. It would be important to plant wetland/riparian plants such as willows, sedges, and rushes along the banks to help shade the channel and stabilize the banks if future flows were increased too much causing erosion. Both Zuellig and this study scored the reach a C (Table 7.2). It appears that Zuellig saw the stream during the same state as highly embedded with no riffles. This just shows the importance of visiting sites with impacted flow regimes on multiple occasions to better determine the stability of the habitat. With an overall grade of D for Reach 3-3 (Table 7.2), this reach has been identified for stream restoration. Assuming a cost of $300 per linear foot (provided by the City of Fort Collins), it would cost approximately $318,000 to restore this reach. Boxelder Creek, Reach 4-1 This reach was considered relatively straight with a sinuosity of 1.2. The surrounding riparian area was an old agricultural field with dense willows, cottonwoods, and other woody vegetation lining the stream. Cattails and upland grasses were also present in areas within the reach. The aquatic habitat diversity was suboptimal with some pool-riffle sequencing, but the fish habitat was excellent with lots of woody debris and many fish seen. There was one object that looked like an old footbridge that may stop fish passage at certain flows, but it could not be confirmed (Figure 7.14). Overall, the reach had a functioning riparian area and excellent fish habitat. To improve habitat, trash should be taken out of the channel just upstream of the reach. This section is behind a housing area and used heavily by the residents, causing the channel to become degraded and possibly impassable by fish depending on the amount of trash in areas. Zuellig scored the reach a C, while this study scored it an A (Table 7.2). The largest discrepancies in score were frequency of riffles and vegetative width. Looking at an aerial photograph from 1999, it appears that the riparian corridor was less vegetated than when this study was conducted, which can explain some of the difference in scores. As for riffles, the flow was high in the channel when assessing the habitat, so there was some benefit of the doubt given to whether it was a riffle or not, but it is presumed that habitat may have increased in the channel since Zuellig’s study. COFC2012.03A_BECS Selected Plan.docx 7-17 Anderson Consulting Engineers, Inc. Figure 7.15 Dense Willows Lining the Left-Hand Side of the Bank. Figure 7.16 Dense Willows in Many Areas of the Reach. Boxelder Creek, Reach 5-2 This reach was considered a meandering channel with a sinuosity of 1.6. The surrounding riparian area was an open field dominated by upland grasses with some dense willows lining the very downstream left-hand side of the bank (Figure 7.15). The flow regime within the reach was slightly affected by some gutter outflow pipes. Although high water was making it hard to discern, there was some pool-riffle sequencing present otherwise it was mostly long runs. Fish habitat was considered suboptimal despite the riffles only being slightly embedded with fines. The reach would benefit from wetland/riparian plants such as willows, sedges, and rushes along the banks for shade and protection. Creating some more riffle-pool habitat would be beneficial although the channel should be viewed again under lower flows to better discern between riffles and runs. Zuellig scored the reach a B, while this study scored it an A (Table 7.2). The largest discrepancies in score were frequency of riffles and embeddedness. There was some riffle-pool sequencing occurring in the reach during the habitat assessment that possibly was not happening when Zuellig did his study, but with no real description of the reach found, it cannot be confirmed. With an overall grade of C for Reach 5-2 (Table 7.2), this reach has been identified for stream restoration. Assuming a cost of $300 per linear foot (provided by the City of Fort Collins), it would cost approximately $351,000 to restore this reach. Boxelder Creek, Reach 5-3 The reach was a meandering channel, sinuosity 1.6, through wide riparian areas with sections of dense willows and cattails mixed with an open area dominated by upland grasses (Figure 7.16). The vegetation was so dense and overhanging the channel that the shading was considered too much and scored as poor. The channel had little to no pool-riffle sequencing, and consisted of a long run in many instances. The water level was high when conducting the assessment, so some of the runs may be glides in lower water conditions. Fish habitat was marginal due to the lack of riffles and embeddedness of the stream bottom. To increase future habitat, it would be beneficial to replace the cattails with wetland/riparian plants such as willows, sedges, and rushes, and look into the grade controls that may be creating a slope to shallow allowing for deposition to embed the stream bottom. Flushing the fines out may reveal some more riffles or even create more riffles with a more appropriate slope. This in turn would provide habitat for macro-invertebrates and areas for fish to spawn. COFC2012.03A_BECS Selected Plan.docx 7-18 Anderson Consulting Engineers, Inc. Figure 7.17 Bare Riparian Area from Trampling. Both Zuellig and this study scored the reach a B (Table 7.2). There were only minor differences with Zuellig scoring the frequency riffles slightly lower. With no site description it is hard to confirm, but perhaps the reaches habitat has not changed much since 1999. With an overall grade of C for Reach 5-3 (Table 7.2), this reach has been identified for stream restoration. Assuming a cost of $300 per linear foot (provided by the City of Fort Collins), it would cost approximately $526,500 to restore this reach. Boxelder Creek, Reach 6-1 The reach was a meandering channel, sinuosity 1.5, through an open field used as a horse pasture. The riparian width was mostly non-existent, as horses have trampled the riparian area leaving many of the banks completely bare and the channel mostly unshaded (Figure 7.17). There was some pool-riffle sequencing, but there was only marginal fish habitat with the stream bottom being moderately embedded. Overall, the reach appeared to be a good example of a stable stretch of river and was only degraded from the presence of horses. If the horses were fenced off from most of the stream and wetland/riparian plants such as willows, sedges, and rushes were planted, the reach would be expected to recover and possibly become an ideal reach for fish habitat. Zuellig scored the reach an A, while this study scored it a B (Table 7.2). This reach would have been scored an A as well except for the trampling from horses degrading the riparian area and causing sediment issues within the channel. It is possible at the time Zuellig inspected the stream there were no horses in the field making the stream excellent habitat. This reach is an easy fix and discussions with the landowners should hopefully resolve the issue. With an overall grade of D for Reach 6-1 (Table 7.2), this reach has been identified for stream restoration. Assuming a cost of $300 per linear foot (provided by the City of Fort Collins), it would cost approximately $378,000 to restore this reach. Boxelder Creek, Reach 6-2 The reach was a relatively straight channel, sinuosity 1.3, and was entrenched downstream, but opened up into an open field at the upstream end. The riparian area was wide and consisted of large cottonwoods, willows, and upland grasses. There was some pool-riffle sequencing and fish habitat was optimal with clean riffles and woody debris in areas. The habitat was optimal and should be protected from future land-use changes. Both Zuellig and this study scored the reach an A (7.2). It seems like nothing has changed much within this reach since Zuellig conducted his study. This may be due in part to the presence of bedrock on the stream bottom and banks that have kept the stream from possibly degrading. Some horse activity was present at the very downstream end of the reach and steps should be taken to fence them out to maintain the habitat. COFC2012.03A_BECS Selected Plan.docx 7-19 Anderson Consulting Engineers, Inc. Figure 7.18 Middle of the Reach with Upland Grasses Being Dominant. Boxelder Creek, Reach 6-3 The reach was a meandering channel, sinuosity 1.7, and ran through an open field consisting mainly of upland grasses with pockets of cottonwoods, willows, and Russian Olives. There was occasional pool-riffle sequencing and fish habitat was considered suboptimal with only a few woody snags and slightly embedded riffles. Bank stability was worse downstream and the failed bank material may be causing the slight embeddedness of the riffles (Figure 7.18). The flow regime may be causing the bank instabilities as base flows seemed elevated from water seeping through the banks in areas. The seepage is presumed to be coming from the large canal that is higher in elevation than the stream. Sediment input may also be contributed from upstream reaches where the channel runs through horse pastures that have trampled bare banks. The landowners should be contacted to see if they could restrict the horses from most of the stream. The channel would benefit from the planting of wetland/riparian species such as willows, sedges, and rushes to helps stabilize the banks. Zuellig scored the reach a B, while this study scored it an A (Table 7.2). The largest differences in scores were Zuellig ranked the frequency of riffles and vegetative width much lower. The open field was an old agricultural field that looks abandoned, so it is possible that at the time of Zuellig’s study, the agriculture was negatively impacting the riparian width. There was an old diversion just downstream of the reach that may have been up and running at the time of Zuellig’s study causing the channel to be more of a glide and having sediment deposit out covering the riffles. This has not been confirmed, but could be the reason behind the differences in scoring. 7.6 WATER QUALITY RECOMMENDATIONS Following the completion of the Conceptual Alternatives Phase it was concluded by City Staff that treatment of stormwater within the Cooper Slough Basin would be addressed according to stormwater criteria imposed upon new development. In addition, it was assumed that treatment of stormwater within the Boxelder Basin would be addressed with future development under the guidance of the Boxelder Basin Stormwater Authority. 7.7 SUMMARY OF COSTS The following is provided as a summary of costs pertaining to both stream restoration and water quality enhancement. COFC2012.03A_BECS Selected Plan.docx 7-20 Anderson Consulting Engineers, Inc. Boxelder Subbasin Stream Restoration Reach 3-1 ......................................................................................................... $780,000 Stream Restoration Reach 3-3 ......................................................................................................... $318,000 Stream Restoration Reach 5-2 ......................................................................................................... $351,000 Stream Restoration Reach 5-3 ......................................................................................................... $526,500 Stream Restoration Reach 6-1 ......................................................................................................... $378,000 Total for the Boxelder Subbasin .................................................................... $2,353,500 7.8 REFERENCES Assessments and Rehabilitation Decision-Making Framework for the Streams of Fort Collins, Colorado State University, Johannes Beeby, Peter Kulchawik, and Brian Bledsoe, PhD, P.E., December 2011. Assessment of Urban Stream Rehabilitation Potential and Effectiveness of Stormwater Mitigation Techniques in Fort Collins, Colorado State University, et al, Larry Roesner, PhD, P.E., Boris Kondratieff, PhD, 2010. Canal Importation Basin, Master Drainage Plan, Anderson Consulting Engineers, Inc., May 2001. City of Fort Collins Water Quality Sensitivity Analysis for the Old Town Basin Memorandum, Anderson Consulting Engineers, Inc., November 2010. City of Fort Collins Water Quality Sensitivity Analysis for the Spring Creek Basin Memorandum, Anderson Consulting Engineers, Inc., November 2010. Stormwater Best Management Practice (BMP) Inventory Project, Colorado State University, Urban Water Center, Jason Messamer, Chris Olson, Dr. Larry A Roesner, PhD, P.E., June 2010. The Canal Importation Basin Water Quality Master Plan Conceptual Alternatives, Anderson Consulting Engineers, Inc., August 2011. CITY OF FORT COLLINS STORMWATER MASTER PLANNING AND FLOODPLAIN ADMINISTRATION DIVISION STREAM REHABILITATION PRIORITY RANKING June 3, 2014 Overall Reach Creek Name Rank Reach Subreach Score Length (ft) Location Associated BMPs Notes Fossil 1 4 1 2.9 2250 Upstream of Lemay through Fossil Park Design needs to incorporate Mail Creek 1-1 Spring 2 1 5 2.5 810 Between RR tracks and Riverside Mail 3 3 1 2.5 980 Directly north of Meadow Passway Construct all proposed improvemnts in Mail Creek BMP Selected Plan* Mail 4 1 1 2.3 3240 Confluence with Fossil Creek, northwest from Fossil Park Dependent on Fossil Creek 4-1 design Fossil 5 1 1 2.3 1120 Between RR tracks and Trilby Rd Spring 6 Remove Edora Dam 2.2 NA Along north side of Edora Park, west of Riverside Ave Spring 7 1 6 2.2 780 Between Riverside Ave and Edora Dam Construct new Edora Park Pond Should be constructed at same time as Edora Dam removal. Spring 8 3 2 2.1 1040 Directly west of Lemay Ave Fossil 9 2 1 2.0 1880 North of Trilby Rd partway through Paragon Point open space Construct new WQ Pond in Prairie Dog Meadow NA Spring 10 Reconnect to Poudre 1.9 NA From confluence with Poudre River through Cattail Chorus NA Fossil 11 9 1 1.9 2130 From Applewood Estates pond through neighborhood to Shields Fossil 12 8 1 1.8 2020 From RR tracks through open space to Applewood Estates pond Stanton 13 1 1 1.8 4630 From confluence with Fossil Creek to Carpenter Rd Construct new WQ Pond at Lemay Ave and Carpenter Road Mail 14 2 1 1.8 1370 Between Mail Creek Ln and Meadow Passway Boxelder 15 3 3 1.8 1180 Directly west of I-25 crossing Will need to be completed in conjunction with Boxelder Regional improvements. Fossil 16 3 1 1.8 1130 Runs southeast partly through the gold course Reach is through the golf course Spring 17 5 1 1.8 1590 Just east of Stover St to just southwest of Stuart St Retrofit Woodwest Detention Pond and Retrofit CSU Vet Hospital Pond* Spring 18 1 4 1.7 870 Between Timberline Rd detention Pond and RR tracks CITY OF FORT COLLINS STORMWATER MASTER PLANNING AND FLOODPLAIN ADMINISTRATION DIVISION STREAM REHABILITATION PRIORITY RANKING June 3, 2014 Overall Reach Creek Name Rank Reach Subreach Score Length (ft) Location Associated BMPs Notes Fossil 22 6 2 1.7 3530 From College Ave east through HOA open space Drop structure removal and irrigation structure needs to be included in this reach. McClellands 23 5 2 1.6 Through Stetson Creek HOA open space Fossil 24 2 2 1.6 3430 Through Paragon Point HOA open space Clearview 25 2 1 1.6 1440 Between Castlerock Dr and Taft Hill Rd Retrofit Deerfield Ponds Spring 26 4 1 1.6 1550 Just west of Lemay Ave to just east of Stover St Boxelder 27 6 1 1.6 1330 Through private property south of Vine Dr Spring 28 2 1 1.5 1070 Between Edora Dam and Welch St Should be designed and possibly constructed at same time as Edora Dam removal. Spring 29 1 3 1.5 1180 Between Prospect Rd and Timberline Rd Foothills 30 1 1 1.5 1470 Between confluence with FCRID and Chase Dr McClellands 31 7 1 1.5 From White Willow Dr west through HOA open space Retrofit Willow Springs Pond Mail 32 3 2 1.5 1490 From Fairway Estates dam south through HOA open space Retrofit Fairway Estates Pond This reach is tied to the proposed flow control on Fairway Dam McClellands 33 6 1 1.5 Through Stetson Creek HOA open space Primarliy land management issues Burns 34 1 1 1.4 1780 From confluence with Fossil Creek north to Shields St Boxelder 35 3 1 1.4 2860 Directly north of Prospect Rd through provate property Will need to be completed in conjunction with Boxelder Regional improvements Fossil 36 6 1 1.4 2410 Through HOA open space along Fossil Creek Pkwy Foothills 37 2 1 1.4 1530 Between Chase Dr and Rigden Pkwy Retrofit Fort Collins High School Pond Primarliy land management issues Boxelder 38 1 4 1.4 Through open space south of Prospect Rd Coordinate with Natural Areas McClellands 39 3 1 1.4 1250 Between Ziegler Rd and Corbett Dr through HOA open space Retrofit Preston Junior High School Pond CITY OF FORT COLLINS STORMWATER MASTER PLANNING AND FLOODPLAIN ADMINISTRATION DIVISION STREAM REHABILITATION PRIORITY RANKING June 3, 2014 Overall Reach Creek Name Rank Reach Subreach Score Length (ft) Location Associated BMPs Notes Boxelder 43 4 1 1.3 1410 Directly east of I-25 crossing through private property Will need to be completed in conjunction with Boxelder Regional improvements Boxelder 44 1 3 1.3 2340 Through open space south of Prospect Rd Coordinate with Natural Areas Boxelder 45 5 1 1.3 770 Through private property north of Mulberry St Spring 46 1 1 1.2 520 From entrance to Cattail Chorus NA west to bike trail crossing Dependent on connection of Spring Creek to Poudre River Fossil 47 7 1 1.2 2610 Between College and RR tracks through natural area Retrofit Brookwood/Applewood Estates Pond Dependent on drop structure removal in Reach 6- 2 Spring 48 7 1 1.2 820 From entrance to Hill Pond west through open space Retrofit Spring Canyon Pond and Construct new Taft/Horsetooth Pond* Boxelder 49 1 2 1.2 1270 Through open space south of Prospect Rd Coordinate with Natural Areas Boxelder 50 5 2 1.2 1240 Through private property north of Mulberry St Boxelder 51 1 1 1.2 1770 From confluence with Poudre River north adjacent to BE Sanitation USGS gage location, Coordinate with Natural Areas Boxelder 52 6 3 1.2 1450 Through private property south of Vine Dr McClellands 53 5 1 1.2 2200 Through private property SE of Stetson Creek neighborhood Dependent on McClellands Reach 5-2 and outfall from Kechter Crossing Spring 54 1 2 1.2 580 Through open space directly north pf Prospect Rd Mail 55 4 1 1.1 Near trash rack at Harmony and College Boxelder 56 5 3 1.1 1880 1 1 Ordinance -- Appropriating $3.75M to construct the Fort Collins/Timnath Boxelder Creek Improvements City Council Meeting June 3, 2014 Kenneth C. Sampley, P.E. Stormwater and Floodplain Program Manager City of Fort Collins 2 Executive Summary The purpose of this item is to appropriate funds in the amount of $3,750,000 to design and construct the Fort Collins/Timnath Boxelder Creek Improvements. ------------------------------- The improvements are outlined in the Council- adopted Sixth Amendment to the Fort Collins/ Timnath IGA (Ord. No. 047 -- 4/1/14) 2 3 BOXELDER CREEK WATERSHED Project Map -------------------------- Fort Collins / Timnath Boxelder Creek Improvements • Lake Canal Crossing of Boxelder Creek • Boxelder Creek Outfall and Prospect Road Improvements • Boxelder Creek at Interstate Highway 25 4 • Feb. 17, 2009 Intergovernmental Agreement (IGA) – Growth Management Areas (GMAs) – Disposition of certain properties – Boxelder Creek Floodplain Issues • Nov. 13, 2012 – BBRSA / Timnath IGA – Timnath (TDA) to contribute financially to BBRSA projects • Nov. 13, 2012 -- 4th Amendment to IGA – Revised Boxelder Creek Provisions and related funding • Apr. 1, 2014 – 6th Amendment to IGA – Fort Collins and Timnath agree to jointly eliminate the original Boxelder Creek Overflow Project and jointly fund, design and construct the Fort Collins/Timnath Boxelder Creek Projects Fort Collins / Timnath Background 3 5 Fort Collins Financial Benefits • Fort Collins saves approximately $4.1 Million: • $2.1 Million savings in total estimated project costs (from $6.1 Million to $4 Million). • $2.0 Million savings as a result of 50/50 cost share of project costs • $1.75 Million of City’s share will be freed-up escrow funds Fort Collins / Timnath Projects 6 Environmental Impacts • No projects within a Fort Collins Natural Area • No construction is anticipated within the 100- Year Poudre River floodplain • Stream Rehabilitation Program (Stormwater Utility) • Program Summary • Boxelder Creek – Lake Canal to Prospect Road • Priority #35 -- Cost Est = $780,000 +/- • Coordination w/developer of Interstate Land Site • All environmental permits (Endangered Species, 404 Permit) will be obtained Fort Collins / Timnath Projects 4 7 Summary Staff recommends approval of the Ordinance to appropriate funds to design and construct the Fort Collins/Timnath Boxelder Creek Improvements. - 1 - ORDINANCE NO. 090, 2014 OF THE COUNCIL OF THE CITY OF FORT COLLINS APPROPRIATING UNANTICIPATED REVENUE IN THE STORMWATER FUND TO DESIGN AND CONSTRUCT THE FORT COLLINS/TIMNATH BOXELDER CREEK FLOOD MITIGATION PROJECTS WHEREAS, in 2009 the City and the Town of Timnath entered into an intergovernmental agreement (“IGA”) regarding Growth Management Areas for the two communities, associated issues authorizing the disposition of certain properties, and stormwater and floodplain issues associated with Boxelder Creek and the “Boxelder Creek Overflow Project”; and WHEREAS, Ordinance No. 047, 2014, authorizing the Sixth Amendment to the IGA was approved on second reading on April 1, 2014, and the Sixth Amendment has since been signed by the parties; and WHEREAS, the Sixth Amendment identifies the scope and locations of the Fort Collins / Timnath Boxelder Creek Flood Mitigation Projects (the “Projects”); and WHEREAS, the total cost of the Projects is currently estimated to be $4,000,000, which amount Fort Collins and Timnath have agreed to share equally in order to timely complete the Projects; and WHEREAS, the City has an existing capital project appropriation of $250,000 which will be applied to project costs: and WHEREAS, the City is to receive $1,750,000 previously deposited in an escrow account for the construction of the Projects; and WHEREAS, the Town of Timnath is contractually obligated to contribute the remaining 50% of the total project costs, up to an amount of $2,000,000; and WHEREAS, Article V, Section 9, of the City Charter permits the City Council to make supplemental appropriations by ordinance at any time during the fiscal year, provided the total amount of such supplemental appropriations, in combination with all previous appropriations for that fiscal year, does not exceed the current estimate of actual and anticipated revenues to be received during the fiscal year; and WHEREAS, City staff have determined that the appropriation of the revenue as described herein will not cause the total amount appropriated in the Stormwater Fund to exceed the current estimate of actual and anticipated revenues to be received in that fund during any fiscal year; and WHEREAS, the City Council has found that appropriating unanticipated revenue in the Stormwater Fund for the purpose of designing and constructing the Fort Collins / Timnath - 2 - Boxelder Creek Flood Mitigation Projects will benefit the Stormwater Utility and City Stormwater ratepayers. NOW, THEREFORE, BE IT ORDAINED BY THE COUNCIL OF THE CITY OF FORT COLLINS that there is hereby appropriated for expenditure from unanticipated revenue in the Stormwater Fund the sum of THREE MILLION SEVEN HUNDRED AND FIFTY THOUSAND DOLLARS ($3,750,000) for the Fort Collins/Timnath Boxelder Creek Flood Mitigation Projects. Introduced, considered favorably on first reading, and ordered published this 3rd day of June, A.D. 2014, and to be presented for final passage on the 1st day of July, A.D. 2014. __________________________________ Mayor ATTEST: _______________________________ City Clerk Passed and adopted on final reading on the 1st day of July, A.D. 2014. __________________________________ Mayor ATTEST: _______________________________ City Clerk Through private property north of Mulberry St Boxelder 57 6 2 1.0 1460 Through private property south of Vine Dr Clearview 58 1 1 1.0 360 Between Avery Park pond and Castlerock Dr Foothills 59 3 B 0.7 From Horsetooth Rd NE through HOA property to Power Trail Retrofit Southmoor Village Pond Clearview 60 3 D 0.6 Between Taft Hill Rd and Hillcrest Dr Foothills 61 2 C 0.6 Between Rigden Pkwy and Power Trail Retrofit Collindale PUD Pond and Retrofit Parkwood East Pond* Page 3 of 3 Coordinate with HOA for drop structure improvements Spring 40 3 1 1.4 1600 Between Welch St and Lemay Ave Spring 41 5 2 1.4 1890 From just SW of Stuart St to RR tracks west of College Retrofit Kensington Pond and Construct new Centre Ave Pond* McClellands 42 4 1 1.3 630 Between Corbett Dr and Rabbit Creek Rd through HOA open space Retrofit Harmony Crossing Pond Coordinate with HOA for drop structure improvements Page 2 of 3 Fossil 19 3 2 1.7 1210 From Lemay Ave southeast partly through the golf course Reach is through the golf course Spring 20 6 2 1.7 1150 Between Centre Ave and Hillpond Retrofit Rossborough Park Pond and Retrofit Wagon Wheel Pond* Coordinate with CSU/Horticulture Center McClellands 21 7 2 1.7 From RR tracks west of Timberline Rd east through neighborhood Retrofit Miramont Pond and Retrofit Oakridge Pond* Page 1 of 3 Habitat Zuellig Parameters Only Zuellig Score Our Score Boxelder Creek 1-1 B B C B B A 1-2 B C A A B A 1-3 B B D B B A 1-4 -- -- -- -- -- -- 3-1 C C B C C A 3-2 B A D C C A 3-3 D C C E C C 4-1 B A A B C A 5-1 -- -- -- -- -- -- 5-2 C B B C B A 5-3 C C A D B B 6-1 D E B D A B 6-2 B A A C A A 6-3 B B B C B A 7.8 Figure: B A --- -- C A C A C C C A --- -- B A B B A B A A B A Of the parameters assessed, only certain parameters were substantially higher and included frequency of riffles, embeddedness, epifaunal substrate / available cover, vegetative width, and vegetative protection. It is reasonable to assume that for many of the streams the vegetative width and protection scores would be higher now than 11 years ago as land-use change from agriculture into residential developments has slowed, allowing for the riparian areas to revegetate and recover to a better condition. This is evident on aerial photographs from 1999 that show many of the streams, especially in the southern portion of the city, were still surrounded by agricultural use, which resulted in a narrower riparian area with less vegetation. As for the other parameters that consistently ranked higher, these can be explained in part by the susceptibility of the modified RBP assessment to seasonality. Depending on when you conduct the assessment, stream habitat can look different. Zuellig conducted his assessments from April to early June in 1999. This is usually a time that has had no flushing flows during the preceding months due to (1) precipitation falling as snow, which dampens the rise in the hydrograph when compared to rain events, and (2) no input from irrigation canals which cause higher base flows and more sediment transport. These low flows can allow for sediment deposition and create an embedded stream. If substantial rains occur in spring, and once irrigation is supplying water to the streams again, the fines can be flushed out and the channel bed becomes less embedded. Assessments conducted for this study were all done from are likely exacerbated by the increase in flow from the leaks. In addition, the leaking irrigation pipe is causing severe erosion right at the pipe which may lead to structural failure. Consequently, the irrigation pipe should be replaced to eliminate the leaking. Overall, the channel is more susceptible to lateral erosion than vertical erosion. Boxelder Creek, Reach 1-3 Within Reach 1-3 a cobble layer is present 0 to 2 feet below the bed surface with exposed claypan in a few areas; and cantilever failures are present in a couple of bends. Undercutting is also prominent in the bends, but only slight in runs. Woody vegetation is dense, especially along the right side of the stream and helps to minimize undercutting (Figure 7.3). Overall, the channel is susceptible 3-3 -- -- -- -- -- 4-1 0% 100% 0% Low Medium 5-1 1% 99% 0% Low Low 5-2 1% 99% 0% Low Medium 5-3 0% 50% 50% Low Low 6-1 1% 99% 0% Low Medium 6-2 25% 75% 0% Low Low 6-3 25% 75% 0% Low Medium 7.1 Figure: