Vantage Bay PUD Final Development Plan Index Master File

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* Vineyard, Lawn and public space irrigation requirements were created with the following equation: [(WIG Seasonal Irrigation Requirement) * [1-(1210 Application Efficiency)]]/12 = required acre-feet per season Interpretation: Table 1 shows the previously stated assumptions in numeric form. Its purpose is to provide the most basic consumption units of each variable within the Vantage Bay water system. These base numbers are scalable to any size or ratio that suits you until the overall consumptive usages reach the limit of 52.4 acre-feet per year or if instant demand reaches 257 GPM. The second limit can be relaxed with the addition of a water storage system to compensate for overuse during peak usage. Table 2 illustrates a potential version of a maxed-out water. These units per variable reflect the current project scope. This table was constructed units found in the current version of the Vantage Bay development plan, information found in the Washington State Department of Health’s “Water System Design Manual: Appendix D” and estimations based on the map of the development. These numbers are subject to change and are only illustrations of possible combination of usages. Observations : Based on the above data, expansion of irrigation would limit the ability to develop the residential units. The grand total in table 2 shows that the vineyard consumptive usage (36.39 are-feet) is the largest draw on the budget. As such, the vineyard constrains the water budget, reducing the projected vineyard totals from 16 acres to 12.86 acres. The difference in vineyard size (3.14 acres) would add an addition 8.9 acre-feet of consumptive use. To alleviate budget constraints on the overall water system there are further refinements that can be made to make more water available. The four possible solutions are: 1) Develop Vantage Bay in phases. Begin with the residential uses and finish with the installation of the vineyard. Through this staged approach, water usage will begin to be documented as the residential units begin to hold families. This documentation will most likely provide smaller indoor and outdoor domestic water data allowing water to be reassigned towards the expansion of the vineyard or public areas. 2) Install Xeriscape and/or mandate it’s use with covenants. By Xeriscaping, residential units will see a drop in outdoor water usage by roughly 30% or 55.8 gallons per year per cubic-foot versus traditional landscaping xiii 3) Invest in a more efficient water delivery system to reduce wasted irrigation water. (i.e. Microirrigation–Subsurface Drip has an application efficiency of 90% . By reducing residential outdoor use, water can be assigned towards the development of the vineyard or other public areas. xiv 4) Combine all solutions to maximize water efficiency in the Vantage Bay water system. ) A system like this could reduce the vineyard consumption use 4.4 acre-feet per season. Index #7