1. Aquatic Life / Habitat Assessment Project PAR 991 June 30, 2006

2. Project Goal u Conduct a comprehensive study to: u Assess aquatic life/habitat improvement alternatives u Develop recommendations for aquatic life/habitat improvements u Prepare a Study Phase Report

3. Project Overview u Segment 15 channel and flow characteristics have been altered considerably due to: u Floodplain & resource development u Urbanizing hydrology u Water supply activities u Bed and bank stabilization

4. Project Overview (cont.) u Overall habitat quality is low for indigenous fish species. u Original conclusion based on 1992 mapping of entire segment u Confirmed by 2005 mapping u Aquatic habitat improvements, including u Flow modification u Physical habitat enhancement

5. Habitat Availability for Target Fish Species Habitat improvements that increase the variety of depth, velocity, substrate and cover regimes will be the most effective for attracting and supporting a diverse fish species assemblage.

6. Project Approach 1. Identify aquatic habitat baseline conditions 2. Develop aquatic life/habitat improvement alternatives 3. Evaluate alternative improvements 4. Select a preferred alternative 5. Establish an implementation program 6. Obtain MOU Agency concurrence

7. Biological Literature Review u Native Fish assemblage predominately supported by a harsher, intermittent flow regime driven mostly by abiotic processes u Urbanization has resulted in environmental conditions dominated by lack of seasonal variability of flow and temperature and greater base flow u Segment 15 Fish Community u 17 fish species common in Segment 15; 5 are non- native species u 20 fish species rarely observed or have the potential to be observed; 7 are non-native species

8. Common Fish Species in the South Platte River * = non-native species

9. GenusSpeciesCommon Names Propst 1982 Goettl 1982 CDOW 1992 CDM et al 1993 CDM et al 1994b USGS 1995 MWRD 1986- 2004 Catostomidae Catostomuscatostomuslongnose sucker XXXXXXX Catostomuscommersoniiwhite sucker XXXXXXX Cyprinidae Cyprinuscarpio*common carp XXXXXXX Notropisstramineussand shiner XXXXX X Pimephalespromelasfathead minnow XXXXXXX Rhinichthyscataractaelongnose dace XX XXXX Semolitusatromaculatuscreek chub XX X XX Fundulidae Funduluszebrinusplains killifish XXX X Poeciliidae Gambusiaaffinis*mosquitofish XXXXX Gasterosteidae Culaeainconstansbrook stickleback XXXXXXX Centrarchidae Lepomiscyanellusgreen sunfish XXXXXXX Lepomis humilisorangespotted sfsh XX X Micropterussalmoides*largemouth bass XXXXXXX Pomoxisnigromaculatus*black crappie XXX XXX Percidae EtheostomaexileIowa darter X X X Percaflavescens*yellow perch XX XXX Ictaluridae Ameiurusmelasblack bullhead XXXX X

10. Rare or Potential Fish Species in the South Platte River * = non-native species

11. GenusSpeciesCommon NamesPropst 1982 Goettl 1982 CDOW 1992 CDM et al. 1993 CDM et al. 1994b USGS 1995 MWRD 1986- 2004 Clupeidae Dorosomacepedianumgizzard shadXX Catostomidae Carpiodescarpioriver carpsuckerXX Cyprinidae Campostomaanomalumcentral stonerollerXX X Carassiusauratus*goldfish XX X Cyprinellalutrensisred shinerXX Hybognathushankinsonibrassy minnowX Hybognathusplacitusplains minnowXX Luxiluscornutuscommon shinerXX X Notropisdorsalisbigmouth shinerXX X Phenacobiusmirabilissuckermouth minnowXX Phoxinuseosnorthern redbelly daceX Fundulidae Fundulussciadicusplains topminnowXX X Centrarchidae Lepomisgibbosus*pumpkinseed X X Lepomismacrochirus*bluegillX X Micropterusdolomieu*smallmouth bass XX Pomoxisannularis*white crappie X X X Percidae Etheostomanigrumjohnny darterXX X X Sandervitreuswalleye X Ictaluridae Ameiurusnebulosus*brown bullheadX Ictaluruspunctatuschannel catfishXX X X

12. Biological Basis for Habitat Improvements Segment 15 resident fish species – particularly natives – provide the basis for development of habitat improvements

13. Flow Impacts on Habitat Improvement Alternatives Habitat improvements must be implemented in reaches of Segment 15 that have sufficient existing and future flows.

14. Segment 15 Water Development Activities Existing and future flow characteristics will affect aquatic habitat u Water rights exchanges u Agricultural water rights acquisition u Development of lined gravel lake storage u Water conservation & efficiency u Future effluent discharges & other return flows u Use of consumable return flows u Chatfield Reservoir Reallocation of flood storage

15. Future Flow Expectations u Approximately 80 cfs of existing consumable return flows. u Existing consumable return flows will be diverted within Segment 15. u Future low flows, at times, will be less than 1954 due to exchanges and agricultural acquisitions. u Decrease in flows as river travels downstream u Significant reduction downstream of Brighton Ditch. u Subtracting 80 cfs from 2002 calculated flows (dry year) represents a reasonable approximation of future low flows.

16. Habitat Improvement Options Identified options mimic typical Segment 15 habitat types u Riffles u Pools u Protective cover

17. Development of Alternatives Site specific based on Habitat Improvement Reaches (HIRs) with 3-tiered approach to evaluation u Tier 1 – Physical implementation u Does the potential exist for appropriate habitat u Retained top 10 HIRs for further evaluation u Tier 2 – Success of implementation based on Channel morphology Infrastructure Ownership Stakeholder cooperation Biological considerations Cost effectiveness Sustainability Regulatory concurrence u Tier 3 – “Deal Breakers” considered

18. Final Alternative Ranking

19. Recommended Alternative Reach 9 –Brantner Ditch diversion to Henderson Road u Diverse habitat elements can be easily implemented u Bracketed by reaches that have high quality habitat u Relatively good existing and future flow conditions

20. Recommended Alternative u 6 backwater pools (11 acres) u 5 riffles u 9 snags u 5,400 feet of spur dikes u 2.5 acres of revegetated banks Proposed improvements include:

22. Backwater Wetland Pools Pool at Reaeration Structure 3

23. Spur Dikes South Platte River Spur Dike at Hwy 85

24. Snags Snag on the Straight River, MN Proposed Snag configurations

25. Riffles Urban Drainage & Flood Control District Grade Control Structure

26. Flow Augmentation Through Chatfield Flood Flow Reallocation u Reach 1 would particularly benefit due to existing zero flow conditions. u Reach has relatively good habitat. u Fish sampling has resulted in high populations. A cooperative agreement to maintain minimum stream flows in Segment 15

27. Calculated Stream Flows at Key Locations March and October 1999 Average Hydrology

28. Calculated Stream Flows at Key Locations January and April 1995 Above Average Hydrology

29. Calculated Stream Flows at Key Locations December and August 2002 Below Average Hydrology

30. Predicted Changes in Average Flow Depth with 80 cfs

31. Predicted Changes in Average Flow Velocity with 80 cfs

32. Maximum Water Depth (ft.) Under Various Flow Scenarios 10 cfs30 cfs50 cfs80 cfsLocation 0.480.790.981.21 600 ft. US of I-270 Bridge 1.081.431.641.89 495 ft. US of MWRD Access Rd. 2.112.222.332.47 1430 ft. US 64 th Ave. 0.110.250.350.48 150 ft. US UPRR Bridge 3.733.883.984.09 2137 ft. US Gardener Ditch