Watershed Management Plan - Mason County

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Chapter 2 WRIA 16 – State of the Watershed noted that its rights vested under federal law and were not subject to determination or compromise under state law. The Skokomish Tribe also has a claim for aboriginal water rights. In 1983, the U.S. Supreme Court in U.S. v. Adair held that when a Tribe retains fishing rights in a treaty, it also retains water rights to maintain in-stream flows of sufficient quality and quantity to support that fishery. The 1974 district court case U.S. v. Washington (which is commonly referred to as the Boldt decision) reaffirmed the Skokomish Tribe’s treaty reservation of fishing rights in “usual and accustomed” fishing area. Such water rights have a priority date of “time immemorial.” These flows have also not been quantified, however, which further complicates efforts by tribes, watershed planning groups, and others to assess water resources in WRIA 16. WRIA 16 water users consume only a small fraction of water flowing through the watershed. However, seasonal and local variations indicate that careful planning and conservation are necessary, especially given other needs, such as fish habitat WATER USE For uses other than Cushman Dam – with an estimated annual use of 333,000 AF/yr (Golder Associates, 2003) – actual use of water is generally less than what is allocated. Although most water use is not metered, the Level 1 Technical Assessment estimated that: • Actual residential water use in WRIA 16 is between 1,000-1,500 acre-feet per year (AF/yr), or less than 20% of the approximately 7,500 AF/yr allocated for community and residential use. Approximately 323 AF/yr of the 1,000-1,500 AF/yr was estimated to be withdrawn from permit-exempt wells. • Water used for irrigation amounts to less than 500 AF/yr, which represents about 6% of the approximately 8,200 AF/yr allocated for this use. 9 • In total, the actual estimated water use in the basin is estimated to be 2,000 AF/yr, or less than 0.07% of the total basin streamflow of 3 million AF/yr. Compared to other watersheds in Washington, the percentage of streamflow used in WRIA 16 is very low (Golder Associates, 2003). However, caution should be used in interpreting this conclusion for two reasons. First, peak water supply and peak water use may not coincide, meaning that in some months a much higher fraction of the stream flow may be used. For example, water demand generally peaks in summer and early fall, when crops, lawns, golf courses, and gardens require watering, just as water supply is at its lowest. (See Figure 3 for a sample hydrograph from the Duckabush River; other WRIA 16 streams that originate in the Olympic Mountains show similar streamflow patterns, whereas lower-elevation streams do not show the second, late-spring peak associated with snow 9 According to Washington’s Water Right Tracking System, acres irrigated applies to a wide variety of irrigation types, including agricultural irrigation, lawn/garden irrigation, and golf course irrigation. page 16 Final Plan for County Adoption – May 11, 2006
Chapter WRIA 16 – State of the Watershed 2 melt). Second, this assessment of water use does not take into account the needs of the other resources supported by WRIA 16’s streams, such as fish habitat. The WRIA 16 Planning Unit, the Skokomish Tribe, and the Department of Ecology are planning to undertake an instream flow process that will help assess and quantify the needs of these other resources. Figure 3. Average Monthly Streamflow in the Duckabush River, 1938-2003 (USGS Gauge 1205400, as reported in Golder Associates, 2003) Average Monthly Streamflow (Acre-Feet) 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 0 Peak due to runoff Oct Nov Dec Jan Feb Mar Apr Month Peak due to snow melt Low late-summer flow May Jun Jul Aug Sep Oct WRIA 16’s water use is expected to increase as permanent and seasonal populations grow. The Level 1 Technical Assessment estimated that residential water use would increase by approximately 265 AF/yr by 2010 (Golder Associates, 2003). Additional increases in water demand would be realized if expansion in agriculture, tourism-related business, or industry occurs, or if the current water right applications are approved. CLIMATE CHANGE In addition to population growth, global climate change is expected to exert a major influence on future water demand. Research and modeling at the University of Washington has indicated that average annual temperatures in the region are expected to increase 2.5 degrees F by the 2020s and 3.8 degrees F by the 2040s. Winter precipitation is expected to increase by about 8% (UW Climate Impacts Group, 2004). Climate change projections have important implications for Pacific Northwest water supplies. In general, rivers that derive some portion of flow from snowmelt (including most WRIA 16 sub-basins) will see Climate change is likely to reduce spring stream flows in WRIA 16 Final Plan for County Adoption – May 11, 2006 page 17
Page 1 and 2: Watershed Management Plan Skokomish
Page 3 and 4: WRIA 16 Summary of Watershed Manage
Page 5 and 6: WRIA 16 Summary of Watershed Manage
Page 7 and 8: WRIA 16 Watershed Management Plan T
Page 9 and 10: Chapter Introduction and Background
Page 15 and 16: Chapter WRIA 16 - State of the Wate
Page 21: Chapter WRIA 16 - State of the Wate
Page 41 and 42: Chapter Recommendations: Water Quan
Page 43 and 44: Chapter Recommendations: Water Qual
Page 45 and 46: 4.2. On-site Septic Systems 4.2.1.
Page 47 and 48: Chapter Recommendations: Water Qual
Page 49 and 50: Chapter Recommendations: Habitat 5
Page 51 and 52: Chapter Other Recommendations 6 ent
Page 53 and 54: Chapter Other Recommendations 6 6.1
Page 55 and 56: Chapter Other Recommendations 6 lan
Page 57 and 58: Chapter Other Recommendations 6 Pla
Page 59 and 60: Chapter Implementing the Plan 7 7.
Page 61 and 62: Chapter Works Cited 8 Hood Canal Co
Page 63 and 64: Chapter Works Cited 8 Puget Sound A
Page 65 and 66: Chapter Works Cited 8 Washington St
Page 67 and 68: Chapter Glossary 9 9. Glossary 303(
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Sub-basin Summaries Appendix A The
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Sub-basin Summaries Appendix A Duck
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Figure 7. Duckabush Sub-basin
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Sub-basin Summaries Appendix A Esti
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Figure 8. Map of the Hamma Hamma Su
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Sub-basin Summaries Appendix A perm
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Sub-basin Summaries Appendix A Figu
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Sub-basin Summaries Appendix A ISSU
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Sub-basin Summaries Appendix A Sout
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Figure 11. Map of the South Shore S
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Sub-basin Summaries Appendix A Depa
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Key Issues and Options - Water Quan
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Key Issues and Options - Water Qual
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Key Issues and Options - Habitat Ap
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Addressing Cumulative or Cross-Cutt
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Addressing Cumulative or Cross-Cutt
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Options for Funding New Efforts App
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Supporting Documents Appendix G App
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Watershed Management Plan - Mason County

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