One could also interpret Task 4 as asking whether the two-year milestone practices, if implemented, would result in the promised load reductions. That is, are the nutrient and sediment load reduction efficiencies, which are assigned to each of the best management practices (BMPs) and used by the Watershed Model to predict load reductions, reasonably accurate? However, as noted in Chapter 2, a comprehensive review of BMP efficiencies was beyond the task and time available for the committee. (See Chapter 2 for additional discussion of BMP efficiencies.)

Based on discussions with U.S. Environmental Protection Agency (EPA) staff, the committee interpreted this task as asking: (1) Is the two-year milestone strategy appropriate to address the Bay’s excess nutrient and sediment loads, and (2) are treatment technologies and land-based BMP practices being implemented as promised in the original two-year milestones, such that the jurisdictions are on track to meet their modeled load reduction goals? These questions, and the data available to address them, are examined separately in the sections that follow.

THE TWO-YEAR MILESTONE STRATEGY

The two-year milestone strategy adopted by the CBP Executive Council simply breaks the overall implementation goals for nutrient and sediment reduction into two-year increments, with the goal of having all actions in place by 2025. At the time they were adopted, the milestones were targeted toward the tributary strategy goals, but since that time, the total maximum daily load (TMDL) has replaced the tributary strategy goals. Starting in 2011, the milestones will be set with the objective of implementing by 2025 all nutrient and sediment reduction practices (including wastewater treatment and BMPs for regulated and unregulated stormwater and nonpoint sources) needed to reach the TMDL and implementing 60 percent of the practices by 2017 (see Chapter 1). The CBP adopted a longer increment for the first milestone (roughly 3 years), although the additional time in no way slows the pace of progress expected for this period. As noted in Chapter 1 (see Table 1-5), the first milestone goals represent approximately 21-22 percent of the nitrogen and phosphorus reductions needed to reach the loading goals—a sizeable first increment. As envisioned by this strategy, the success of implementation strategies would be evaluated by the CBP every 2 years, making each jurisdiction and its elected and appointed officials more accountable for successes and shortfalls. The two-year milestone strategy is dependent on tracking and accounting processes to produce reliable implementation data (see Chapter 2).

The overall impact of wastewater treatment upgrades and newly-implemented BMPs can be significantly reduced if additional controls are not specifically included to offset development and population growth. In



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