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;.--,. CONDUCT FURTHER RESEARCH This report documents a significant investigation of the dynamics of the Colorado River delta. There are many questions relevant to the delta's restoration that remain unanswered, and more questions are sure to arise. At present, several areas of research stand out as priorities. . Develop a water budget for the delta. More research is needed on water availability, consumption, and demand in the delta so that an accurate water bud- get can be created. All stakeholders need to agree on accounting techniques for the development of a wa- ter budget. A water budget would help in the search for ways to preserve delta ecosystems, and it would answer key questions about the amount, quality, and timing of water releases to satisfy basic ecological needs. A water budget developed with credible ac- counting measures will play a key role in bringing various stakeholders together in the search for alter- natives for delta preservation. More accurate information also would provide a foundation for any negotiations for additional water or for changes in water management. IBWC, SEMARNAP-INE BOR, CAN research institutions . Run experimental flushing flows. Pulse flows are clearly important to the sustainability of delta ripar- ian and wetland vegetation, but the role of pulse flows in flushing accumulated pollutants and silts is not well understood. A demonstration and testing pro- gram of artificial floods should be designed to increase freshwater flows in wetland and riparian areas, particularly where human contact occurs (Zones 4 & 5). This demonstration should test a flow of 300,000 af (3.7 x 108 m3), at a rate of 3500-7000 cfs (100-200 m3/ s), to determine its efficacy in purging accumulated pollutants and prompting revegetation in riparian areas. SEMARNAP-INE CNA IBWC, BOR, EPAPRONATURA . Investigate the effects of flood release timing on delta vegetation. Although pre-development floods oc- curred primarily in late spring, observed winter flood releases were successful in stimulating the growth of delta vegetation. Today' s floods are predictable to the extent that the BaR can plan reservoir releases. The impacts of flood flows on delta vegetation and other biota should be studied in order to document the vari- ability of response according to timing, and an optimal season for floods should be determined. SEMARNAP-INE, CNA, IBWC, BOK EPA PRONATURA research institutions . Identify ways to sustain native vegetation in ripar- ian and wetland areas. More research is needed on recruitment and growth of cottonwood and willow trees. IBWC, CNA BOR, EPA SEMARNAP-INE . Inventory resident and migratory birds in the delta. Although some work has been done to identify spe- cies that use delta habitats, there is no comprehensive study of birds that depend on them. In particular, this work should focus on birds in the cottonwood- willow riparian areas that have been identified as high habitat value. Research institutions . Quantify the relationships between freshwater flows and delta and Gulf aquatic species. Further study is needed to determine the needs of aquatic species, in- cluding endangered species, commercial fisheries and others. Research Institutions, FW$ SEMARNAP-INE . Explore opportunities for ecotourism. Further study of the economic potential of ecotourism in the delta and the Sonoran Desert region could help attach an economic value to healthy ecosystems and create strong local constituencies in favor of their protec- tion. Researchers from the University of Arizona, Biosphere Reserve managers, and members of the Johnson ejido have begun to promote birding, canoe- ing, kayaking, and other activities to bring economic benefit to local communities. Local communities, SEMARNAP-INE IMPLEMENT SITE-SPECIFIC RESTORATION (Zones are defined in Chapter 3. See Figure 6.) Colorado River Delta Riparian Corridor (Zones 2-4) . Identify measures to restore a perennial source of water in riparian and wetland areas to support cot- tonwood-willow habitat and its high biodiversity value. IBWC, CNA BOR, EPA SEMARNAP-INE . Develop a stream channel maintenance program with CNA to stop or minimize the removal or disturbance of wetland vegetation. IBWC, CNA, BOR, SEMARNAP-INE 46