- Animals: fish
- Natural Resources/Environment: biodiversity, habitat enhancement, indicators, riparian buffers, riverbank protection, soil stabilization, wetlands
- Production Systems: agroecosystems, holistic management
Understanding the impacts of agriculture on water quality is an extremely important issue. In the Umatilla basin in eastern Oregon agriculture is a predominant part of the economy. But the effect of agriculture on water quality and its impact on local salmon populations is creating much concern about best management practices in the area. The proposed project will develop a means for assessing water quality in the basin through the use of macroinvertebrate community structure. Macroinvertebrates are ideal for assessing water quality because they respond to a variety of pollutants and can rapidly respond to increases in water quality. The proposed project will not only develop the methodologies for using macroinvertebrates in water quality assessment but will also use these methods for assessing the effectiveness of riparian conservation easements on water quality. While conservation easements are seen as a major means of improving water quality, their effectiveness is not well understood. If we are to promote good stewardship of agricultural lands, we must understand the utility of best management practices such as riparian conservation easements.
Project objectives from proposal:
The proposed project is a study of the non-point source pollution effects on the Umatilla River mainstem, and is geared toward the promotion of good stewardship of the river as a resource. The project involves developing a biomonitoring protocol that will assist water managers in determining factors that significantly affect the river. This research will also specifically look at the efficacy of buffer zones in improving overall water quality. This project will assist in a better understanding of the river ecosystem and serve as an aid in making protection of the endangered salmon compatible with agricultural practices.
The Umatilla River in Eastern Oregon drains a watershed strongly dominated by agriculture and with a history of severe disturbances to the river resulting in the extinction of native salmonids. The upper reaches of the river run through the lands of the Confederated Tribes of the Umatilla Indian Reservation (CTUIR), a community reliant on both agriculture and tribal harvest of local steelhead and salmon. The lower river is also dominated by agriculture that is dependent upon water withdrawals from the river for irrigation. The entire river has been channelized over the years to maximize the use of the fertile flood plains for agriculture and to accommodate the development of roads and railways.
One of the critical consequences of agriculture is non-point source pollution. Non-point source pollution is the accumulation of natural and human caused toxins on non-target systems, such as pesticide runoff effects in groundwater and ultimately in the nearby river systems. The extent of the impact of agriculture on river systems is not yet quantified and is a matter of debate.
By comparing the diversity and abundance of the endemic invertebrate fauna at a number of locations along the Umatilla mainstem, we will be able to determine the regional health of the system. Aquatic invertebrates are good ecological indicators, responding to a variety of human disturbances. The different families and genera have different ranges of tolerance to pollution levels in the water that can indicate the condition of the river.
Agricultural practices also impact abiotic factors in riparian and river ecosystems. Runoff from crops can increase sediment levels and the levels of chemical toxicity due to the use of pesticides and fertilizers. It is also common along the Umatilla River to see the crops approach within feet of the river bank, with the native cottonwood galleries removed completely. The effects of the loss of riparian canopy cover along the river are increased water temperatures and increased sunlight exposure, which allow algal populations to thrive. Channelization of the natural riverbed has also had a major impact on the river as a habitat for salmon, as removing the natural meanders causes a decrease in overall water quality.
The CTUIR has taken an active role in attempting to mitigate the impacts of agriculture on the Umatilla River through a variety of efforts including collaborative arrangements with local growers that involve conservation easements. The growers are paid for the land adjacent to the river, which is then allowed to recover natural flora as a “buffer zone.” These buffer zones decrease runoff effects and allow the river to resume natural meanderings and braided channels that are critical for water quality and habitat composition. The re-growth of the natural cottonwood galleries will also provide canopy cover for the river, which will have effects on water temperatures. The trees also are a source of woody debris, which creates optimal habitat conditions for the salmon populations of the Umatilla River.
We plan to sample the invertebrate communities in a number of locations along the Umatilla River mainstem. Samples will be taken from three types of locations. Primary samples will be taken at “reference” sites, where the least amount of disturbance has occurred. These areas may not be pristine, but represent the ideal condition for the river in that region. Samples will also be taken from “test” sites, areas that have had high levels of agricultural disturbance in close vicinity to the river. Finally, samples will be taken in areas running through conservation easements that have been established for the recovery of salmon in the Umatilla River.
Water quality will also be measured in various capacities, such as water temperature, conductivity, turbidity and alkalinity. Other measurements such as canopy cover, water velocity and habitat complexity will also be considered in the site evaluations.
The invertebrate community composition will be determined at each site and compared between reference, test and easement sites using multivariate statistics. From this data a “model” is developed of the expected invertebrate community at a given location if that location is in good or high quality condition. The actual condition of the site is given a score based on a comparison of the actual community composition to the expected community composition.
Site Selection: The first step in the project is to identify reference sites, sites in the best condition given the local land use. These sites will be chosen following the methods outlined by Drake (2004). Test sites will be found at areas where little to no riparian vegetation exists and agricultural fields directly abut the river bank. Reference and test sites will be found with the assistance of the expert knowledge of fisheries biologists with the CTUIR and ODFW. Finally, four sites that drain through conservation easements will be selected with the assistance of CTUIR biologists.
Sampling: Aquatic invertebrates will be sampled from these sites during July and August following the methods outlined by Barbour et al. (1999). July and August are the hottest months in the Umatilla basin and thus are the times when water temperatures are highest and the impact of riparian vegetation on water temperatures is most likely to be observed.
Model Development: The development of multivariate models for bioassessment is widely used as a means for examining the condition of river reaches (Hawkins et al. 2000), and the methodologies have been worked out (Clarke et al. 1996; Canale 1999). However, the model needs to be refined for each geographic location based on the unique groups of aquatic taxa present, the hydrogeology of the area, and the specific land uses of the area.
Outreach: A critical aspect of this program involves broadly impacting the communities near the river by opening lines of communication between researchers and the public. For any effort toward sustainability to be successful, it must be conceived with the intention to involve the communities that are supported by the resources provided by the systems. Without effective communication, any positive results in management will be short lived. By attending local watershed council meetings, writing for local publications and participating in outreach events, we will make the connection to the community. Through collaboration and communication, the needs of both agriculturist and conservation parties can be included in the solution.
Use of the Model: Recovery of the Umatilla River is an important undertaking not only to conservationists, but also to the people of the Confederated Tribes, as they depend on local salmon populations. The community is dedicated to finding a solution to preserve this unique system. Buffer systems have provided a tentative answer, but their efficacy is yet to be determined. If proven to be successful means of recovery for the Umatilla River, similar attempts can be made statewide, perhaps with even further reaching implications.
The proposed project will assist greatly in determining the effectiveness of conservation easements on improving conditions in the Umatilla mainstem. We expect that the data will show degraded invertebrate communities where the river has been most disturbed by agriculture in comparison to the reference sites, and a strong recovery trend in the regions employing property easements. This research will contribute to the base knowledge of current conditions of the Umatilla River, and have general implications on other systems with similar environmental factors. These implications can then assist in policies that govern land use in riparian areas that can benefit both the salmon conservation efforts and the need of agriculturalists by helping to determine whether conservation easements can be considered a best management practice.
Funding is requested for two years. Two years of sampling are required to capture inter-year variability in water levels, water temperatures, and invertebrate community composition. In May and June of the first year (2006) reference, test and easement sites will be identified with the help of local fisheries biologists. Sampling will be conducted in July-August of 2006 and 2007 and samples will be processed (i.e., collected invertebrates will be sorted, counted, and identified) during the fall and winter of each year. The model will be developed and the condition of the test and easement sites determined in the late winter of 2007/2008.
Outreach will be conducted throughout the entire process. We plan to give presentations to the local watershed council and tribes at the beginning of the project to outline our objectives and then to continue to give presentations to update the local community on our progress. Outreach will also involve communicating our findings to the scientific community through presenting at a regional EPA meeting (EPA Region 10 NW Biological Assessment Workgroup Meeting) and publication of a peer-reviewed manuscript.
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