Stream: Tabeguache Creek (Lower Segement) Executive Summary

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Biological Data Below the headgate of the Templeton Ditch, this segment is characterized by a slightly wider stream valley, and larger substrate. The stream channel is larger because of high- volume, short- duration snowmelt runoff flows from Shavano, Campbell, and Spring creeks. The creek supports a narrowleaf cottonwood - sandbar willow - skunkbrush sumac - chokecherry riparian community. Fishery surveys indicate that the lower part of the reach is important for sensitive species habitat. Stream samples during spring spawning season have documented flannelmouth sucker and roundtail chub. In addition, surveys have documented the presence of red shiner and speckled dace. It is likely that both the sensitive and non - sensitive species move into the creek from the San Miguel River to spawn, most likely when they are cued by rising stream temperatures. Field Survey Data BLM and CDOW staff used the R2Cross methodology to quantify the amount of water required to preserve the natural environment to a reasonable degree. The R2Cross method requires that stream discharge and channel profile data be collected in a riffle stream habitat type. Riffles are most easily visualized, as the stream habitat types that would dry up first should streamflow cease. This type of hydraulic data collection consists of setting up a transect, surveying the stream channel geometry, and measuring the stream discharge. Biological Flow Recommendation The CWCB staff relied upon the biological expertise of the cooperating agencies to interpret output from the R2Cross data collected to develop the initial, biologic instream flow recommendation. This initial recommendation is designed to address the unique biologic requirements of each stream without regard to water availability. Three instream flow hydraulic parameters, average depth, percent wetted perimeter, and average velocity are used to develop biologic instream flow recommendations. The CDOW has determined that maintaining these three hydraulic parameters at adequate levels across riffle habitat types, aquatic habitat in pools and runs will also be maintained for most life stages of fish and aquatic invertebrates (Nehring 1979; Espegren 1996). For this stream, four data sets were collected with the results shown in Table 1 below. Table 1 shows who collected the data (Party), the date the data was collected (Date), the measured discharge at the time of the survey (Q), the accuracy range of the predicted flows based on Manning's Equation (240% and 40% of Q), the summer flow recommendation based on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 hydraulic criteria. It is believed that recommendations that fall outside of the accuracy range of the model, over 250% of the measured discharge or under 40% of the measured discharge may not give an accurate estimate of the necessary instream flow required. Table 1: Data Party Date Q 250 % -40% Summer (3/3) Winter (2/3) BLM/CDOW 6/19/2003 2.51 6.3-1.0 out of range 2.86 BLM/CDOW 6/19/2003 2.13 5.3-0.9 out of range 1.80 BLM/CDOW 6/2/2006 8.1 20.2-3.2 3.89 out of range BLM/CDOW 6/2/2006 8.09 20.2-3.2 5.62 out of range -3-