Understanding thermal mixing, water quality improvements, and algae dynamics with the pulsing of releases from Jordan Reservoir

Description

The Cape Fear River Basin was added to a nationwide program called The Sustainable Rivers Program (SRP) in 2016. SRP is a joint program between The Nature Conservancy (TNC) and the US Army Corps of Engineers (Corps) to improve the health of rivers by analyzing how the Corps operates their infrastructure, such as the release of water out of dams. The SRP attempts to analyze the effects from dams and use reservoir operations to enhance and manage downstream (and sometimes in lake) ecosystems. The Cape Fear River Basin was chosen for the SRP because of its complex human-ecology relationships, the expert stakeholders in the basin, and because the Corps-owned B. Everett Jordan Dam (Jordan Dam) has potential to influence fish and wildlife habitat, water quality, and other natural resources. The Cape Fear River Basin contains over two million people (2010 census), one-fifth of the state’s population. This includes growing urban areas of Durham, Greensboro, Pittsboro, Fayetteville, Wilmington and other cities, which contribute urban runoff into the river, but many of which also get a portion of their drinking water from this waterbody. The basin also supports 95 species of recreational fish, 42 rare aquatic species, as well as streamside habitat containing some of the oldest trees east of the Rocky Mountains; some of which are over 2000 years old (Stahle, 2012). Natural and human environments rely on the Cape Fear River, making its water quality and water quantity of the utmost importance. There have been multiple harmful algal bloom outbreaks behind Lock and Dam 1. These algal blooms are harmful to the health of the aquatic ecosystem, resulting, at times, in fish kills. The Cape Fear River also has many drinking water users, especially near locations of historic algal blooms. The algal blooms impact the treatment capacity of the many water supply systems on the Cape Fear River. The Corps, TNC and expert stakeholders have collaborated and identified flow recommendations that may reduce these harmful algal blooms. Flow recommendations include pulsing events to flush lower velocity (pooled) areas, drought conditions, temperature improvements, and like issues. This request seeks to study the impacts of releases on water quality downstream. Brief Description of Anticipated Work: The objectives of this work are to: Understand thermal stratification of the Cape Fear River, especially near Lock and Dam 1; Correlate different flow rates with potential thermal mixing of the water column; Track water quality constituents, especially chlorophyll a, as it relates to flow Relate the Corps’ water management to water quality and investigate the influence of releases out of Jordan Reservoir

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