4

Biological and Water Quality Monitoring

The Committee made several comments and recommendations associated with the design, purpose, integration, and adequacy of the water quality and biological monitoring programs in its first report (NRC, 2015). In particular the Committee raised concerns about the apparent lack of integration between the water quality and biological monitoring programs, the difficulty of making system-wide estimates of target species population densities and trends given the reliance on non-randomized sampling of selected index reaches, the inability to assess whether changes in nutrient status are leading to changes in the frequency and magnitude of algal blooms because of insufficient detection limits of phosphorous and nitrogen, and the inability to determine population densities and spatial distribution of the invertebrate target species such as the Comal Springs riffle beetle.

In response to the Committee’s recommendations, the Edwards Aquifer Authority (EAA) established two working groups to assess the water quality and biological monitoring programs, respectively, and make necessary modifications, and they added a Ph.D. level scientist (Dr. Chad Furl) to its staff to assist with these efforts. This evaluation of the two monitoring programs provided the EAA with an opportunity to integrate more closely the water quality and biological monitoring programs to provide efficient and seamless measurement of variables important to inform the modeling efforts and ensure that species of interest maintain adequate population levels. These working groups met throughout the spring of 2016 and issued a joint report (EAHCP, 2016) for consideration by the EAA Implementation Committee. As shown in Tables 4-1 and 4-2, the working groups comprised representatives from various stakeholder groups and included members of the Sci-

TABLE 4-1 2016 Water Quality Monitoring Program Work Group

TABLE 4-2 2016 Biological Monitoring Program Work Group

ence Committee. While there was no overlap in membership between the two working groups, Steven Raabe from the San Antonio River Authority was appointed as joint chair of both the water quality and biomonitoring working groups, presumably in an effort to coordinate recommendations between the two working groups. It appears that the ecological modeling team was not represented in these working groups. This is unfortunate because inclusion of one or more members of the modeling team would have allowed for better integration between the modeling and monitoring efforts, which is important for ensuring that the data collected by the monitoring programs are directly useful in the model calibration and validation efforts. The two working groups have now disbanded, having completed their tasks. The EAA should consider forming a standing working group on monitoring that would meet as needed to provide advice and outside perspective on the EAA’s monitoring program.

The joint report of the two working groups (EAHCP, 2016) presents a number of modifications to the existing water quality and biomonitoring programs (see Tables 4-3 and 4-4). The revised monitoring program eliminates monitoring of a large list of contaminants that have not been found to occur in detectable concentrations in the spring systems, and adds sampling of fish tissue for particular contaminants, one additional sonde measure-

TABLE 4-3 Final Recommendations for the Water Quality Monitoring Program

BioMP = biological monitoring program

EAA = Edwards Aquifer Authority

IPMP = Integrated Pest Management Plan

PPCP = pharmaceutical and personal care products

SOURCE: EAHCP (2016).

TABLE 4-4 Final Recommendations for the Biological Monitoring Program

EAA = Edwards Aquifer Authority

RBA = rapid bioassessment

SRP = soluble reactive phosphorus

TCEQ = Texas Commission on Environmental Quality

TPWD = Texas Parks and Wildlife Department

SOURCE: EAHCP (2016).

ment station in each spring system, and rapid bioassessment protocols. The resulting water quality and biomonitoring programs are better integrated, more targeted to the species of concern, more efficient, and provide more standardized monitoring of the overall health and quality of the aquatic ecosystems. A detailed discussion of the progress made on monitoring the CSRB is provided in Chapter 5.

Nutrients. As a result of the Committee’s recommendations in NRC (2015) and the deliberations of the monitoring working groups, the EAA has made a number of modifications to the monitoring of nutrients (nitrogen and phosphorus). Of particular note is the lowering of the detection limit for phosphorous. The detection limit for soluble reactive phosphorus will be lowered to 3-5 µg/L from the current detection limit of 50 µg/L. The lower detection limit for soluble reactive phosphorus will enhance the ability to detect increasing or decreasing trends of what is likely the limiting nutrient in the system and help provide an early warning of eutrophication, which can lead to depleted levels of dissolved oxygen.

The detection limit for nitrogen species will remain at 50 µg/L for nitrate and 100 µg/L for ammonia. The working group recommended that the detection limits not be changed for nitrogen species after examining data collected thus far and finding that almost all values were well above the detection limits. The EAA will also partner with the Clean Rivers Program, which also does routine monitoring of nutrients in the spring and river systems. In particular, it appears that the EAA will rely on Clean Rivers Program data for nitrogen and for total phosphorus, while continuing to collect data for soluble reactive phosphorus in house. It appears that the Clean Rivers Program uses adequate methods and quality assurance/

quality control protocols. It was not clear, however, whether the Clean Rivers Program samples at the same locations and frequency as the EAA. It is important that these sampling efforts are co-located in space and time so that the data can be used to assess nutrient effects on the spring and river systems. In addition, to enable future interpretation of nutrient monitoring data, it is important that the many analyses be performed on the same water sample.

PAHs. Prior monitoring efforts have shown that the level of contaminants is generally low in the spring and river systems, with one important exception. Recently, the concentration of polycyclic aromatic hydrocarbons (PAHs) was detected at levels as high as 62 mg/kg in a location in the San Marcos River (Blanton and Associates, 2016). This is well above a probable effects concentration of 22.8 mg/kg designed to protect biota (MacDonald et al., 2000). PAHs exposure leads to a narcosis reaction in invertebrates that can result in adverse effects from mild disruption of cell membranes to mortality (Burgess, 2007). If found to be widespread throughout the river system (which is not suggested by the current data) elevated PAHs could lead to significant risks to the listed species that are not currently being addressed by the sediment removal efforts or other monitoring and habitat protection measures. Efforts to identify the significance of these elevated PAH sediments should be undertaken. The frequency and extent of high concentrations of PAHs should be established by more extensive sampling in areas where elevated levels have been identified.

A source of PAHs in urban areas without significant point sources is coal tar-sealed parking lots. Indeed, coal tar sealants may constitute the vast majority of PAHs in adjacent sediments (MacDonald et al., 2000). The EAA banned coal tar as a parking lot sealant over the aquifer’s recharge zone in Hays and Comal Counties in 2012. San Marcos passed a coal tar sealant ban in May 2016, while San Antonio passed a coal tar ban in July 2016. New Braunfels does not have a coal tar ban. If the parking lot sealant is the source of the PAHs observed in the San Marcos River, these bans will lead to reduced sediment PAH concentrations over time.

The actual risks to listed species as a result of exposure to elevated PAH levels is unknown. This is because substantial quantities of PAHs, particularly from coal tars, may be tied up in largely non-bioavailable forms (Cornelissen et al., 2005), such that their presence in sediments does not necessarily suggest that elevated risks are present. If it is not possible to substantially reduce PAH concentrations through sediment removal and source control, evaluation of bioavailability of the PAHs in the sediment should be considered.

Performance Monitoring of Minimization and Mitigation Measures. One addition to the monitoring program is the requirement that groups involved in riparian habitat improvement institute monitoring to assess the effectiveness of the improvements (EAHCP, 2016). This is a step in the right direction, and it directly addresses a recommendation of NRC (2015) to performance monitor the minimization and mitigation (M&M) measures. Ideally, all M&M measures that are implemented as part of the Habitat Conservation Plan (HCP) should be integrated into one conceptually unified monitoring program. These M&M measures are often multi-year in scope, such that it may take additional years of monitoring to evaluate the success of the measures. It would be best if the performance monitoring of M&M measures could be integrated into the existing water quality and biological monitoring programs. This vision conceptualizes monitoring as one multifaceted program that collectively addresses information needs associated with water quality, biology, modeling, and M&M measures.

For example, the EAA will add one continuously recording water quality sonde to each river system. Data from these sondes will provide valuable information on dissolved oxygen and other parameters. In addition, the EAA should consider deploying the miniDOT dissolved oxygen sensors used in the Landa Lake dissolved oxygen study as part of the routine monitoring program. These data, in conjunction with the multiparameter water quality sonde, will provide important, highly resolved spatial and temporal data on dissolved oxygen in Landa Lake. This is an example of how selected measurements first made during Applied Research projects can be integrated into the monitoring program.

CONCLUSIONS AND RECOMMENDATIONS

The main goal for the water quality and biological monitoring programs should be to develop a single, integrated program that provides the basic information needed to assess compliance with the HCP. The monitoring programs are designed to provide long-term data that will allow the EAA and others to assess trends in water quality and biology. The following specific recommendations suggest a few steps in this direction.

The monitoring program should include the measurements needed to monitor the performance of the broad suite of minimization and mitigation measures. Relying on the individual Applied Research projects or M&M activities to provide these data is unrealistic as these projects and measures are not designed nor funded over the long term, even though it may well take multiple years for the effects of these projects to be realized.

The monitoring program should include the long-term data required to test and inform continuous refinements of the ecological model. The

ecological model will need to be continuously assessed and refined, and long-term data collected by the monitoring program will be critical to this effort. It is important that the modeling team be involved in the design of the monitoring program to ensure that the variables being measured are the ones that are most important for model assessment.

The frequency and extent of high concentrations of PAHs should be established by more extensive sampling in areas where elevated levels have been identified. If it is not possible to substantially reduce PAH concentrations through sediment removal and source control, evaluation of bioavailability of the PAHs in the sediment should be considered.

REFERENCES