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=25 <br /> However, scientific knowledge and understanding alone cannot effectively consider the unique <br /> characteristics of this watershed and lake in developing an improved management approach. <br /> Water quality management policy is an essential component in deciding the most effective way to <br /> maintain and improve water quality in Falls Lake, now and in the future. The science provides clear <br /> evidence regarding specific management actions that can meet the water quality standard for <br /> chlorophyll-a throughout the lake. The cause-and-effect aspects of nutrients in this watershed and <br /> lake cannot be dramatically changed. Despite significant reductions in nutrient loading to Falls Lake <br /> since the mid-2000s, chlorophyll-a concentrations have remained stable. While the chlorophyll-a <br /> concentrations are above the standard of 40 pg/L in some parts of the lake, there are no reports of <br /> impacts to water treatability, fish kills, algal scums, or mats. This evaluation indicates that the <br /> current water quality standard for chlorophyll-a is not well correlated to uses in this lake and is <br /> therefore not applicable to Falls Lake. The standard is incorrect for this system and cannot be <br /> achieved. Thoughtful and effective management actions, consistent with the scientific findings and <br /> feasible to implement, are needed to protect water quality in Falls Lake. The characteristics of this <br /> watershed and lake indicate that dramatic changes are not possible. A eutrophic Falls Lake will <br /> always exist. <br /> A reasonable management objective should be to prevent a trophic condition that will impede <br /> designated uses. This watershed is becoming more urban and suburban, and that transition will <br /> continue. Development in the watershed is an essential economic factor for this region and the <br /> jurisdictions within the watershed. Land use is shifting away from its historic composition to more <br /> intensely developed areas within the watershed. The New Development Rules currently in place <br /> mitigate this shift, but long-term changes in the hydrology and nutrient balance within the watershed <br /> are still expected. Controls on runoff from new development manage the first inch of runoff from a <br /> developed site. While most rainfall events in our region do not exceed one-inch, higher rainfall <br /> storms, sometimes several inches, are becoming more frequent. A portion of storms greater than <br /> 1 inch bypasses treatment and delivers untreated flow and nutrients to Falls Lake. Larger storms <br /> also saturate pervious areas in the watershed including unmanaged lands. Saturated soils result in <br /> surface and subsurface transport of nutrients to streams. <br /> Without other watershed mitigation efforts, nutrient loading to Falls Lake will continue to increase <br /> over time. Development increases the amount of impervious surface and results in compacted soils. <br /> These changes alter the hydrologic and water quality properties of the development site and <br /> downstream waters. Land preservation is a critical safeguard for keeping the watershed as natural <br /> as possible, particularly considering a recent decision by the US Supreme Court regarding protection <br /> of wetlands that do not have a "continuous surface connection to waters of the US" (Sackett versus <br /> EPA, Docket number 21-454). Other waters may also be at risk depending on interpretation of the <br /> decision. Land conservation should be a voluntary aspect of the revised management strategy and <br /> should be recognized by the State as a critical component of a long-term nutrient management <br /> strategy. The Raleigh Watershed Protection Program has a target of preserving 30,000 acres of high <br /> priority lands by 2045. Retrofits on existing land use are also useful, but 75 percent of the <br /> watershed is currently forested, wetlands, or other unmanaged lands. The Interim Alternative <br /> Implementation Approach (IATA) is a sustainable model for keeping the watershed as stable as <br /> possible as it includes land conservation as an eligible practice in addition to more conventional <br /> stormwater control measures and best management practices. <br /> Unmanaged land in this watershed is a critical reason that lake water quality continues to support <br /> designated uses. The composition of the watershed, implementation of new development rules, and <br /> the improvements that have been made since the baseline year of 2006 have resulted in a stable <br /> trophic condition. There is a tremendous opportunity to structure a management approach that is <br /> broadly supported, economically viable, and aimed at an achievable goal. This document identifies <br /> 6 <br />