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1999 Progress Report: Restoring and Maintaining Riparian Ecosystem Integrity in Arid Watersheds: Meeting the Challenge through Science and Policy Analysis
EPA Grant Number: R827150Title: Restoring and Maintaining Riparian Ecosystem Integrity in Arid Watersheds: Meeting the Challenge through Science and Policy Analysis
Investigators: Maddock, Thomas , Baker, Victor R. , Colby, Bonnie G. , Glennon, Robert J. , Stromberg, Julie
Current Investigators: Maddock, Thomas , Baird, Kate , Baker, Victor R. , Breckenridge, Cabell , Colby, Bonnie G. , Glennon, Robert J. , Stromberg, Julie
Institution: University of Arizona , Arizona State University - Main Campus
Current Institution: University of Arizona
EPA Project Officer: Stelz, Bill
Project Period: January 15, 1999 through January 1, 2002
Project Period Covered by this Report: January 15, 1999 through January 1, 2000
Project Amount: $849,638
RFA: Water and Watersheds (1998)
Research Category: Water and Watersheds
Description:
Objective:The objectives of this project are to: (1) develop a methodology to quantify the complex hydrologic interactions to variations in streamflow, stream geomorphology, evapotranspiration, and groundwater within a riparian corridor; (2) quantify changes in structure, function, and biotic integrity of the riparian community in response to these hydrologic interactions and to anthropogenic influences such as land use changes, streamflow diversions, and groundwater pumping; (3) develop a hydrologic/ecology model (paradigm?) to provide a framework for examining alternative land and river management practices and assess potential risks to the biotic integrity of the riparian ecosystem from the anthropogenic manipulation of the hydrology and ecology systems; (4) develop an economic model to assess the cost (utility?) of the hydrologic and ecologic management alternatives within the context of the local community; (5) develop procedures that will provide the management institution(s) with scientifically sound information on the current status of the resource, and the expected economic and ecological outcomes of management alternatives; and (6) evaluate the institutional aspects of water resource management to identify changes necessary to implement desired management practices. Progress Summary:
The project is to further community-based environmental protection by integrating hydrologic models, a riparian ecosystem integrity index, and economic analyses into a user-friendly decision support system (DSS). Coupled with legal analysis, this integration is to assist local governments and stakeholders in understanding the impact of development on the particular watershed and in evaluating different strategies for achieving environmental restoration from a scientific, economic, and legal perspective. The project is focusing on arid watersheds for which there exists considerable instrumentation on which to build and refine the hydrologic and ecologic models. The proposal brings together expertise from five essential disciplines whose knowledge is critical to restoring rivers in the arid West: hydrology, ecology, geomorphology, economics, and law. We are to refine existing hydrologic models in the areas of riparian evapotranspiration and surface-groundwater interactions. A riparian ecosystem integrity index is being developed based on landscape, community, and population level traits. Field studies are being conducted to refine our understanding of the linkages among groundwater, surface water, and ecological variables.
Hydrologic and Ecologic Activities. During the first year, the hydrology group has been focusing on gathering the required information to model the South Fork Kern River basin and improving the estimates of riparian evapotranspiration (Et). Towards these ends, an extensive 8-week summer field season was completed. A permanent meteorological tower adjacent to the river was constructed and fully instrumented while a mobile unit measured within canopy conditions. The tower unit continues to measure information on the selected climatic and hydrologic variables. Additional soil moisture and temperature, and groundwater depth and temperature recording devices were installed along two river transects. Surface water flow measurements are being collected at several key points along the river. To obtain detailed elevation profiles, transects stretching the width of the riparian zone were surveyed and tied to known U.S. Geological Survey (USGS) points. Vegetation data were collected along the same transect lines. All measurement locations (climate, groundwater, and transect points) were located with a Global Positioning System. Stem flux measurements were used to determine evapotranspiration from several age classes of cottonwood and willow trees late in the growing season. These data are being analyzed in conjunction with the tree structure, hydrologic, and climatic information.
To compare Et estimates from measured stomatal conductance and stem flux, both were measured on a single willow tree. To obtain total leaf area, the tree was stripped of all of its leaves and total leaf area calculated from the leaf area to leaf dry weight relationship developed. This information will be used to improve the evapotranspiration module. We are still in the early stages of data analysis but the results appear intriguing. The use of two meteorological towers has allowed us to begin quantifying the microclimate created within the riparian canopy. Joint detailed Et and abiotic measurements are helping us elucidate how the key abiotic parameters combine with tree physiology to determine the amount of water required by riparian trees. Early season Et data and the response of Et to groundwater withdrawal still need to be addressed. We conducted in-depth field studies on two biotic community types in the San Pedro Basin, Populus-Salix forests and Sporobolus wrightii grasslands, to identify metrics that were sensitive indicators of site moisture availability. Populus-Salix biotic community type. For the Populus-Salix study, we selected nine sites along the San Pedro River. The sites range from ephemeral to perennial. Four sites were located in the upper basin (National Riparian Conservation Area) and five were in the middle basin (Cascabel area). We measured vegetation variables from three categories: individual productivity measurements, population abundance and size structure measurements, and community composition measurements. We measured the productivity and population variables on two cohorts each of P. fremontii and S. gooddingii, one that had established in 1991 and the other in 1979. The vegetation data were collected in May/June and again in August/September of 1999. At these same sites, data were collected three times per year (June, August, and October) on abundance and composition of terrestrial arthropods. "Sweeps" were made from the foliage of P. fremontii, S. gooddingii. and Tamarix spp. The results indicate that S. goodingii is more sensitive than P. fremontii to changes in ground water level, with productivity measures including May/June shoot leaf area and May/June leaf size changing with groundwater depth across sites only for S. gooddingii. Shoot leaf area was the most sensitive indicator. Stem density of the younger cohort of both species declined with depth to groundwater. Generally, the biotic variables showed stronger correlations with groundwater depth than with surface flow frequency. Few significant correlations were found for the variables measured during the wet, monsoon season (August/September). Preliminary results for the arthropod community analysis indicate that there were fewer numbers of orders of arthropods at the driest sites. Abundance and composition of insects varied considerably between the three different plant species.
We selected 12 sites that supported Sporobolus wrightii grasslands and that spanned gradients of soil moisture, depth to groundwater, and flow frequency. Eight sites were in the San Pedro watershed and four were in the nearby Santa Cruz watershed. We measured stem water content and several indicators of plant structure and productivity during the mid-summer dry season and late-summer wet season of 1999. We sampled the S. wrightii plants three times per year for abundance and composition of the terrestrial arthropod communities. May/June live biomass and percentage of green stems varied significantly with depth to groundwater. As for the Populus-Salix stands, there were greater differences between sites in S. wrightii productivity and biomass structure during the mid-summer dry season than during the late summer wet season. For many arthropod orders, abundance of individuals was significantly lower at the driest sites.
Economic Activities. Our work has focused on identifying economic activities related to instream and consumptive uses of water in the two case study areas and estimating the magnitude of local income, jobs, and business activity related to differing water uses. We have established regular contact with local business leaders, government officials, and land managers to learn more about land and water use patterns. A survey of businesses linked to recreational use of the riparian corridor is planned for the South Fork study area. The feasibility and desirability of surveying visitors to specific sites in the South Fork Valley are being evaluated.
An economic model of costs and benefits associated with restoring riparian areas is being constructed. Relevant literature in resource economics and related fields is under review. The model and its application to case study areas will form the basis of a Master's thesis for one of the project GRAs.
Legal Activities. For the Kern River site, we first documented the physical location and landownership patterns along the South Fork of the Kern, giving background to the region's history, describing the population centers, providing an economic setting, and outlining both the surface water users and groundwater users. Second, background information is being collected on the watershed stakeholders, which are: (1) prominent landowners and water users within the watershed, (2) the Kern River Audubon Preserve, (3) local communities and municipalities (4) recreationists, and (5) federal agencies. We are examining California groundwater and surface water laws. California, like Arizona, has a most unfortunate set of rules that largely treat as different entities groundwater and surface water. Understanding these rules, in particular the rights that are claimed in the South Fork of the Kern, is critical to the understanding of what management options are available. We also are looking at the controversy surrounding Lake Isabella. The Southwest Center for Biological Diversity has filed a lawsuit challenging under the Endangered Species Act (ESA) the regulations for administrating water flow from Lake Isabella. Operation of this reservoir is critical not only to the downstream water users, principally the agricultural community, but also at low flows it impacts the groundwater system above the dam in the South Fork of the Kern. For the San Pedro, we have begun to outline the various management options for the river. In particular, we have focused on the possibility of creating either an Active Management Area or an Irrigation Nonexpansion Area under Arizona law. We also have begun studying the role of the ESA in the role of managing the river. The ESA has potential application in both the San Pedro and the South Fork of the Kern River.
Future Activities:Each of our research groups?hydrology, ecology, economics, and law?will continue on their present course of research, reporting, and publication. During the next year, we will continue with the planned research and model development. Journal Articles:
No journal articles submitted with this report: View all 36 publications for this project
Supplemental Keywords:water, watersheds, groundwater, ecosystem indicators, restoration, habitat, integrated assessment, decision making, survey, socioeconomic, compensation, conservation, environmental assets, social science, ecology, hydrology, economics, law, socioeconomic surveys. , Ecosystem Protection/Environmental Exposure & Risk, Economic, Social, & Behavioral Science Research Program, Water, Scientific Discipline, RFA, Ecosystem/Assessment/Indicators, Water & Watershed, Restoration, Aquatic Ecosystem Restoration, decision-making, Mercury, Economics & Decision Making, Hydrology, Watersheds, Ecology and Ecosystems, risk assessment, arid watersheds, ecosystem valuation, public policy, socioeconomics, watershed restoration, econometrics, community-based research, ecology assessment models, decision making, ecological recovery, riparian ecosystem integrity, conservation, GIS, aquatic ecosystems, integrated assessment, community involvement, riparian ecosytem integrity, restoration planning
Progress and Final Reports:
Original Abstract
2000 Progress Report
2001 Progress Report
Final Report