Review of the Edwards Aquifer Habitat Conservation Plan Report 1 (2015) / Chapter Skim
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4 Monitoring
4 Monitoring
Pages 114-141
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From page 114... ...
Finally, the monitoring plan needs to provide basic information to support the development and evaluation of hydrologic and ecological models designed to understand and forecast spring flow and target species responses to changes in spring flow. In this first report the Committee focuses on the biomonitoring and water quality monitoring programs.
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From page 115... ...
has developed a complex biomonitoring plan that covers many physical, chemical, and biological aspects of the San Marcos and Comal spring and river systems. While the program is focused on the abundance and spatial distribution of the target species (fountain darter, Texas wild rice, Comal Springs riffle beetle)
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From page 116... ...
4-2) Kayak and GPS Twice a year and during critical low flows Fountain darter April, July, Aug., Oct.
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From page 117... ...
10 springs at each of 3 Cotton lures Twice a year and during locations: Spring Run 3, critical low flows along the western shoreline of Landa Lake, and near Spring Island Macroinvertebrate April, Oct. 4 index reaches (Fig.
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From page 118... ...
4-3) GPS Twice a year and during critical low flows Fountain darter May, July (dip net only)
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From page 119... ...
Within these rivers, discrete points are sampled continuously for water temperature and occasionally for other water quality parameters during low-flow-triggered sampling events. "Representative reaches" are short segments of the rivers that are used as index stations and, similarly, "representative springs" are index
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From page 120... ...
120 FIGURE 4-2 Invertebrate, salamander, Texas Master Naturalist, and representative sample reaches (includes aquatic vegetation mapping, drop-net sampling, presence/absence dip net sampling, macroinvertebrate community) surveys within the Comal River study area.
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From page 121... ...
MONITORING 121 FIGURE 4-3 Upper San Marcos River representative sample reaches, salamander count sites, water quality sampling and fixed 4-3 newphotography sites. Figure station SOURCE: BIO-WEST (2014b)
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From page 122... ...
122 REVIEW OF THE EDWARDS AQUIFER HABITAT CONSERVATION PLAN FIGURE 4-4 Fish community sampling segments, and dip net timed survey sections (blue) for the Upper San Marcos River.
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From page 123... ...
MONITORING 123 FIGURE 4-5 Fish community sampling segments, and dip net timed survey sections Figure 4-5 new (blue) for the Lower San Marcos River.
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From page 124... ...
Care should be taken to clarify that data from these index sites are not necessarily scalable to the entire river system. For the remainder of this report, the term "representative reach" is replaced with "index site" or "index reach." It is possible that the EAA will determine that from time to time it is important to be able to scale inferences on population density of fountain darters or other target species to the entire spring and reach system.
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From page 125... ...
Potential sampling of fountain darter in a manner that would be scalable to the entire system is discussed further in the section on biomonitoring of fountain darter. Biomonitoring Methods Texas Wild Rice and Submersed Aquatic Vegetation San Marcos.
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From page 126... ...
In the Old Channel and New Channel reaches, data from the index reaches measured either in 2013 or over the 2001–2013 time period did not follow the actual SAV species coverage in the entire section measured in 2013; however, in Landa Lake the data matched for both time periods. Because of the apparent sensitivity and variable response of SAV to flow conditions, particularly in the Comal River, it would be best to either sample the total river more frequently than every 5 years or increase and/or randomize the sampling locations if a more accurate representation of SAV throughout the river is desired.
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From page 127... ...
It would also be timely to consider special studies related to the use of index sites to indicate fountain darter trends. These special studies could be performed for a limited time to confirm or even improve the interpretation of the standard year-to-year monitoring.
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From page 128... ...
Comal Springs Riffle Beetle As part of the HCP, invertebrates in the Comal system, including the Comal Springs riffle beetle (CSRB) , Peck's Cave amphipod, and Comal Springs dryopid beetle, are sampled using two methods.
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From page 129... ...
Interestingly, the biomonitoring conducted during 2013 found that the Texas wild rice and fountain darter populations were unaffected by the drought conditions, while the CSRB, Comal Springs salamander, and Peck's Cave amphipod all were negatively affected. These short-term responses to drought level flows suggest that the CSRB may be the most sensitive of the listed species, warranting more thorough investigations to better understand the distribution and life history of this species and the other listed invertebrates within the Comal and San Marcos systems.
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From page 130... ...
as a surrogate species, to better understand how physical and chemical changes that may occur with lower spring velocities will impact CSRB survival. These studies could be reasonable to better describe the tolerances of CSRB and mechanisms for its survival under low flows, but only if life history information on CSRB confirms that M
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From page 131... ...
Even less is understood about other threatened invertebrates such as the subterranean Comal Spring dryopid beetle and Peck's cave amphipod, and there have been fewer monitoring efforts. Additional life history and distribution studies are needed for these rare species as well, and a new approach to identifying and quantifying common habitat of these invertebrates warrants additional consideration, investigation, and resource investment.
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From page 132... ...
Standard macroinvertebrate biomonitoring programs are common throughout the United States and could easily be accomplished by the current expertise of the contractors of the EAA. WATER QUALITY MONITORING PROGRAM Water quality monitoring has occurred at various locations in the Comal and San Marcos springs and river systems for more than 10 years.
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From page 133... ...
The sampling is widely dispersed; taking the regular surface water sampling and the augmented stormwater sampling into account, contaminants are measured in unfiltered samples from 13 and 11 locations in the San Marcos and Comal Springs and river systems, respectively. Baseline sampling for the current list of constituents is appropriate, but if no significant concentrations are observed, further sampling for these parameters should be eliminated or conducted at reduced frequency and/or at fewer locations in each spring and river system, as planned (personal communication, Ed Oborny, BIO-WEST, 2014)
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From page 134... ...
constituents listed in constituents listed in constituents listed in Appendix A Appendix A Appendix B Upper Landa Lake 2×/year for 1×/year for (near Spring Island) constituents listed in constituents listed in Appendix A Appendix B Lower Landa Lake 2×/year for 1×/year for (above outfalls)
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From page 135... ...
Lower Old Channel 2 storms/year for (above Hinman constituents listed in Island) Appendix A Comal River (above 2 storms/year for confluence with constituents listed in Guadalupe River)
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From page 136... ...
for complete set^ Sink Creek 2×/year for 2 storms/year for 1×/year for constituents listed in constituents listed in constituents listed in Appendix A Appendix A Appendix B Spring Lake 2×/year for 1×/year for constituents listed in constituents listed in Appendix A Appendix B Sessoms Creek 2×/year for 2 storms/year for 1×/year for constituents listed in constituents listed in constituents listed in Appendix A Appendix A Appendix B City Park 2×/year for 1×/year for constituents listed in constituents listed in Appendix A Appendix B Rio Vista Dam 2×/year for 1×/year for 15 min. for temp, DO, constituents listed in constituents listed in pH, turbidity, Sp.
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From page 137... ...
Cond. Willow Creek 2 storms/year for constituents listed in Appendix A *
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From page 138... ...
Neither approach seems to be consistent with the preliminary nature of the problem identification phase that currently defines the water quality sampling program, but one or both would be needed to quantify contaminants introduced by stormwater events. Nutrient Monitoring Although the list of water quality parameters monitored is generally appropriate, the Committee has concerns about the monitoring of nutrients, especially phosphorus.
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From page 139... ...
If the EAA finds it is necessary to provide system-wide estimates of population densities of target species rather than relying on trends and index stations, it will need to invoke special studies or conduct sampling using randomization techniques. For example, a special study to determine the representativeness of the fountain darter trends estimated in index reaches would sample for darters very broadly and then examine the uncertainty associated with using the index information to infer densities and abundances at broader scales (groups of reaches and system-wide)
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From page 140... ...
It is unclear whether there is a process for integrating information across the two monitoring programs in order to provide a full assessment of biological and environmental conditions. For example, it was confusing that data for phosphorus was found in the biomonitoring report, but not the water quality monitoring report.
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From page 141... ...
2013. 2014 Water Quality Monitoring Program Strategy for Comal Springs and San Marcos Springs in Support of the Edwards Aquifer Habitat Conservation Plan.
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