ARKANSAS RIVER, LAKE FORK 2012 The station just below County Road 11 (LF1) is routinely sampled as part of the protocol to monitor fish population changes relative to heavy metal cleanup in the Leadville mining districts. Cleanup within the Lake Fork basin is largely coordinated through the Lake Fork Watershed Working Group (LFWWG). Three additional stations were sampled in the Lake Fork below Turquoise Reservoir in 2006, 2010, 2011, and 2012. This narrative will compare and contrast current and historic aquatic biota differences within this reach with implications for future management. The Colorado Division of Wildlife (CDOW) extensively sampled the fish population in the Lake Fork below Turquoise Reservoir in 1994 (see earlier Inventory Reports). Brown trout dominated the fish community just above Halfmoon Creek. Many large brown trout were collected at this station. Numerous young of the year (YOY) brown trout were collected. Brook trout were consistently more prevalent upstream of Willow Creek. Brook trout density was low just below Colorado Gulch consisting of small individuals. Brook trout numbers increased dramatically above Colorado Gulch to Dunn Diversion, however, fish remained small. Brown trout YOY were absent in this area. Brook trout density declined significantly above Dunn Diversion. Metal seeps from the Sugarloaf wetland and the Bartlett and Dinero Tunnels may have affected fish survival. Fish were absent at the next station upstream. Sugarloaf Gulch may be diluting the water enough to where a marginal population exists just above Dunn Diversion. Brook and brown trout reproduction was largely absent just below the Dinero Tunnel outfall. The fish community consisted of larger individuals that probably migrated in from downstream reaches. Contamination from Sugarloaf wetlands and Bartlett and Dinero Tunnels likely affect fish reproduction and survival downstream to at least Dunn Diversion. Trout density and biomass increased significantly in 2012 (Tables 1 and 2), particularly at upstream sites. Decreased metals loading associated with lower spring and summer flow likely accounts for improved trout survival. Trout composition, age structure, and species distribution has remained consistent since 2006. Brown trout continue to dominate the fish community below Colorado Gulch to the Arkansas River. Colorado Gulch enters the Lake Fork at County Road 5A. Brook trout were most prevalent above Willow Creek in 1994. Brown trout are successfully reproducing and recruiting to the next age class from below Colorado Gulch to the Arkansas River. Fry survival continually improves in a downstream fashion as well. This upstream species shift coupled with improved brown trout fry survival could have several plausible explanations. Heavy metal loading from Colorado Gulch or other nearby sources may have declined allowing successful brown trout reproduction and recruitment. Or, brown trout may be naturally out-competing brook trout in an upstream fashion. However, competition does not explain improved brown trout fry survival. Improvements are likely a combination of these two factors. Given adequate water quality brown trout typically out-compete other slamonids in streams of this type. Brook trout continue to dominate above Colorado Gulch where fry survival and recruitment to successive year classes has improved since 2006.
Table 1. Brown Trout Population Biometrics in the Lake Fork of the Arkansas River below Turquoise Reservoir, 1994-2012. /Metric 1994 2006 2010 2011 2012 N/acre lbs/acre N/acre lbs/acre N/acre lbs/acre N/acre lbs/acre N/acre lbs/acre Just Downstream of County Road 11: 430.1 88.3 352.0 114.0 355.0 132.0 488.0 122.0 865.0 145.0 0.5 Miles Below State Highway 300: 213.0 82.0 178.0 123.0 128.0 104.0 841.0 218.0 0.5 Miles Below County Road 5A: 75.0 18.0 4.0 4.0 73.0 6.0 217.0 25.0 400 Feet Above Dunn Diversion: 8.8 6.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Table 2. Brook Trout Population Biometrics in the Lake Fork of the Arkansas River below Turquoise Reservoir, 1994-2012. /Metric 1994 2006 2010 2011 2012 N/acre lbs/acre N/acre lbs/acre N/acre lbs/acre N/acre lbs/acre N/acre lbs/acre Just Downstream of County Road 11: 15.3 4.3 --- --- 2.0 1.0 5.0 2.0 9.0 1.0 0.5 Miles Below State Highway 300: 25.0 8.0 18.0 3.0 53.0 12.0 142.0 34.0 0.5 Miles Below County Road 5A: 14.0 2.0 39.0 14.0 11.0 1.0 106.0 6.0 400 Feet Above Dunn Diversion: 119.2 6.0 388.0 50.0 483.0 42.0 596.0 38.0 1009.0 71.0
The above fish population changes indicate an improving water quality condition. Brook trout, a metal tolerant species, dominate above Colorado Gulch. Fry survival and recruitment has improved in recent years while brown trout remain rare, a less metal tolerant species. Brown trout dominate, however, below Colorado Gulch to the Arkansas River. Reproduction, fry survival, and recruitment have improved recently suggesting improved water quality conditions below Colorado Gulch. Mining remediation efforts in the Lake Fork watershed mining districts appear to be working as evidenced by fish population response. An Instream Flow Incremental Methodology (IFIM) study was initiated on the Lake Fork in 2010 to investigate the relationship between flow and fish habitat with the goal of working with the Bureau of Reclamation (BOR) to best manage flows for fisheries. This study was led by Nicole Vieira (Aquatic Toxicologist) and Tracy Kittell (Design Engineer) of the CDOW. Field data was collected and Physical Habitat Simulation (PHABSIM) was performed in 2010. Flow operation recommendations are currently being discussed with BOR. Management Recommendations: 1) Stocking: Not recommended. Most of the land is privately controlled and the current population sustains itself naturally. 2) Regulations: Special fishing regulations are not biologically justified. 3) Habitat Improvement: Continue involvement in water quality cleanup efforts in the Lake Fork basin below Turquoise Reservoir with the LFWWG. Continue to negotiate water releases from Turquoise Reservoir with BOR to enhance aquatic habitat and the fish population in the Lake Fork. Participate with private landowners to improve instream and riparian habitat (primarily between State Highway 300 and County Road 5A). This is largely dependent on securing public access or may occur via the Natural Resource Damages (NRD) restoration process. 4) Access/Facilities: Explore the possibility of securing public access on private sections of the Lake Fork. 5) Information/Education: Dependent on public access.
Appendix A Table 1. Arkansas River Brown Trout Density (no/acre) Near Salida, Fall 1981-2012. 1981 147.7 1982 135.1 60.4 1983 217.7 128.9 1984 243.5 164.5 1985 228.7 1986 168.5 1988 184.9 94.6 1990 254.6 33.4 1991 239.6 1992 242 1993 202.8 1994 187.5 34.5 156.7 1995 193.4 1996 274.4 47.3 282.9 1997 180.4 1998 192.6 61.3 214.2 1999 282 2000 204.6 102.1 268.7 2001 229.7 2002 391.5 142 252.2 2003 450.9 2004 310 111.9 233.8 2006 313.7 150.7 2007 222 49.0 2008 140.8 53.9 180.4 2009 154.2 2010 308.0 80.0 229.0 2011 177.0 55.0 2012 211.4 99.8 223.6 Note: Spring samples before 1999, Fall since 1999 Table 2. Arkansas River Brown Trout Biomass (lb/acre) Near Salida, Fall 1981-2012. 1981 67.8 1982 76 1983 78.3 1984 115.8 1985 108.3
1986 79 1988 92.3 1990 128.9 21.4 1991 135.3 1992 134.6 1993 108.5 1994 100.9 19.6 78.6 1995 78 1996 105.4 21.3 111.7 1997 97.6 1998 85.9 35.2 119 1999 114 2000 62.7 37.8 87 2001 91.4 2002 223.9 91.5 146.2 2003 146.2 2004 139.4 61.1 109.2 2006 172.6 105 2007 116.5 26.0 2008 89.7 39.2 121.1 2009 100.5 2010 170.0 45.0 149.0 2011 102.0 40.0 2012 133.0 72.4 171.8 Note: Spring samples before 1999, Fall since 1999 Table 3. Arkansas River Brown Trout (>= 14"/acre) Near Salida, Fall 1981-2012. 1981 3.4 1982 9 3.8 1983 5.5 5.6 1984 8.2 5.3 1985 7.9 1986 3.7 1988 5.3 10.4 1990 7.5 6.5 1991 8 1992 9.4 1993 6.1 1994 2.9 4.4 7.8 1995 3.7 1996 3.9 5.4 5.4 1997 5.7 1998 0.9 4.4 4.8 1999 7
2000 7.4 12.3 15 2001 4.1 2002 56.3 36.1 50.4 2003 30 2004 28.9 23.4 19 2006 21.3 34 2007 7.3 3.4 2008 24.5 11.5 19.1 2009 32.6 2010 27.5 10.7 51.5 2011 11.9 8.4 2012 51.0 32.9 119.1 Note: Spring samples before 1999, Fall since 1999 Table 4. Arkansas River Rainbow Trout Density (no/acre) Near Salida, Fall 1981-2012. 1981 0.5 1982 0.4 1983 3.8 1984 3.2 1985 0.9 1986 44.3 1988 25.4 0.5 1990 7.5 6.9 1991 31 1992 29.1 1993 18.1 1994 12.4 6 1995 35.1 1996 25.6 4.9 11.5 1997 19.6 1998 12.9 0.9 3.6 1999 14.3 2000 22 2.7 17.8 2001 7.7 2002 3.2 14.3 4.5 2003 6.2 2004 33.1 9.4 18.3 2006 32.1 12.8 2007 19.4 0.0 2008 19.9 3.2 17.2 2009 22.0 2010 24.0 2.0 10.0 2011 60.0 0.0 2012 40.2 6.3 34.2
Note: Spring samples before 1999, Fall since 1999 Table 5. Arkansas River Rainbow Trout Biomass (lb/acre) Near Salida, Fall 1981-2012. 1981 0.2 1982 0.2 1983 1.3 1984 1.8 1985 0.4 1986 14.9 1988 11.9 0.3 1990 8.5 2.2 1991 17.6 1992 20.5 1993 13.8 1994 12.9 4.3 1995 25.7 1996 23.8 4.5 6.2 1997 32.6 1998 19.8 0.8 3.4 1999 10.3 2000 11.4 2.5 2001 8.1 2002 2.8 19 2.6 2003 2.1 2004 32 3.4 12.9 2006 16.7 12.8 2007 13.2 0.0 2008 13.8 3.1 15.1 2009 19.5 2010 22.0 2.0 14.0 2011 36.0 0.0 2012 37.3 6.3 42.8 Note: Spring samples before 1999, Fall since 1999 Table 6. Arkansas River Rainbow Trout (>= 14"/acre) Near Salida, Fall 1981-2012. 1981 0 1982 0 1983 0 0 1984 0 0 1985 0
1986 0.1 1988 3 0 1990 2.9 0 1991 2.7 1992 2.3 1993 10.1 1994 4.2 1.3 0 1995 13.9 1996 30 1.2 0.5 1997 1.3 1998 7.4 0.3 0.3 1999 2.2 2000 0.9 2.1 3.7 2001 2.6 2002 1.5 2.3 2003 0.8 2004 1.8 7 2006 3.4 3.3 2007 2.7 0.0 2008 1.9 1 7.4 2009 8.2 2010 7.8 1.2 8.2 2011 6.6 0.0 2012 23.5 3.5 16.7 Note: Spring samples before 1999, Fall since 1999 Table 7. Arkansas River Brown Trout Density (no/acre) Near Leadville, Fall 1985-2012. AR1 AR3a AR4 Reddy AR5 AR5b AR6a M-H AR6 LF1 EF1 1985 67.8 1991 882 194 62.7 66.8 344 1994 657.1 50.6 509.2 111.8 430.1 305.7 1997 400.9 55.1 146.4 115.1 251.9 337.7 1999 341.8 178.2 183.8 122.8 132.7 79.5 663.3 586.1 2001 392.7 249 316.5 216.6 200.9 99.3 448.6 584.8 2002 834.5 806.3 698.9 456 290.1 284.3 1093.2 796.5 2003 434.7 606.4 330 241 238.4 291.8 1031.2 548.8 2004 263.6 373.4 395.7 282.2 333.6 108.4 327.3 476.8 2005 598.3 696.9 426.7 404.6 301.5 325.4 454.2 2006 422 384 460 303 258 290 352 507 2007 441 115 106 75 2008 309 318 374 181 195 162 520 537 2009 417 314 529 267 274 257 309 382 2011 370 335 275 135 229 204 163 136 261 488 670 2012 788 1064 687 438 800 565 560 410 602 865 589 * AR1 and AR3a sampled in 1989 instead of 1991
Table 8. Arkansas River Brown Trout Biomass (lb/acre) Near Leadville, Fall 1985-2012. AR1 AR3a AR4 Reddy AR5 AR5b AR6a M-H AR6 LF1 EF1 1985 30.5 1991 122.9 22.7 30.9 54.1 60.3 1994 97.2 14.5 102.7 54.1 88.3 33.3 1997 110.9 12.7 43.7 50.9 61.6 53.5 1999 69.7 30.9 72.4 59 60.5 27.5 111.6 77 2001 73.3 61 143.2 73.7 79.2 39.9 105.3 79.5 2002 131.6 146.2 242.2 69 127.9 92.3 130.5 96.9 2003 84 137.6 145.5 77 93.4 82.7 144.8 96.7 2004 87.9 112.6 173.6 114.4 133.3 47.2 79.7 98.7 2005 115.5 167.8 213.7 94.6 105.6 126.7 90.9 2006 89 109 230 110 109 114 104 2007 92.4 25 56 39 2008 68 103 188 76 108 158 129 2009 93 103 235 80 145 105 143 89 2011 86 106 148 135 73 101 79 53 113 122 109 2012 184 256 353 121 151 266 135 89 144 145 90 *AR1 and AR3a sampled in 1989 instead of 1991 Table 9. Arkansas River Brown Trout (>= 14"/acre) Near Leadville, Fall 1985-2012. AR1 AR3a AR4 Reddy AR5 AR5b AR6a M-H AR6 LF1 EF1 1985 2.9 1991 0 0 8.1 17.5 0 1994 0 1.8 9.4 10 7.4 0 1997 0 0 2.6 11.1 10.9 0 1999 0 0 30.2 10.7 14.3 0 20 0 2001 0 0 7.3 14.8 3.7 8.3 0 2002 0 0 72.7 7.1 32.8 11.6 8.9 0 2003 0 0 51.4 31.9 8.2 11.3 0 2004 0 0 67.3 27.7 33.5 10.2 2005 0 6.7 95.5 14.1 10.7 35.6 0 2006 0 0 94 23 25 35 0 2007 0 3 27 2008 0 0 79 20 30 21.3 67 0 2009 0 0 75 13 42 18 20 2011 0 3 81 32 17 21 15 12 20 36 0 2012 0 35 188 34 23 86 34 17 24 45 0 *AR1 and AR3a sampled in 1989 instead of 1991
Table 10. Arkansas River near Leadville sampling sites. Number Location AR1 AR3a AR4 Reddy AR5 AR5b AR6a 1/2 mile upstream of CR 55 M-H 1/4 mile upstream of CR 55 AR6 1/2 mile downstream of CR 55 Just downstream of Tennessee Creek 1/4 mile below California Gulch Just upstream of CR 44 on Smith Ranch 1/4 mile below Iowa Gulch 1/2 mile downstream of Hwy 24 crossing at Empire Gulch 1/4 mile below Stone Bridge LF1 Just downstream of CR 11/FR 160 EF1 Just upstream of Hwy 91 crossing