Civil Engineering Reference
In-Depth Information
Based on this evaluation, water supply alternatives are developed in their rank order,
as needed to serve water demands into the future. Associating key water supply mile-
stones with demand levels instead of dates is called event-driven planning (Figure
8-23). Because it is difficult to accurately forecast land use, population, and water
demands beyond about 5-10 years, use of EDP enables the water supply planner to
identify a plan that is responsive to future demographic changes.
WATERSHED MANAGEMENT
Increasingly, integrated water resources management is being used for long term plan-
ning over an entire watershed. The term ''watershed'' has a strict definition in hy-
drology as the land area that drains to a given point. However, in the regulatory
framework, the use of the term watershed has been broadened to effectively mean
''problem-shed.'' In this chapter, the term ''study area'' has been used. Either way, the
concept is to manage the water resources of a reasonably large area in order to bracket
the principal water resources issues at hand, but not paralyze the planning process.
The key drivers for watershed planning could be water needs, river water quality,
groundwater contamination, endangered species, land-use changes, flood control, rec-
reation, hydropower, navigation, water rights adjudication, and competing water inter-
ests, but more likely a combination of these factors.
Stakeholder involvement is critical to successful water resources management. Al-
though it may be tempting to try to enlarge the study area and solve a broad range of
water resources issues within a study, recent history has shown that the difficulty of
coming to consensus is geometrically proportional to the number of stakeholders and
driving issues. A more appropriate stakeholder involvement standard is consent. Con-
sidering that each critical stakeholder effectively holds a veto in the process, the so-
lutions must be acceptable enough to all critical stakeholders to keep them from
exercising that veto.
Phase 1
Destination
Base Water Demand
Phase 1
Water Import
Wastewater
Recycling
Existing Capacity
Water Demand After Conservation
Time
Fig. 8-23.
Event-driven water supply planning
