Every USACE Civil Works Mission Area is faced with challenges related to aging infrastructure and a backlog of operations and maintenance. The majority of USACE dams throughout the country were constructed over 50 years ago and are beyond the planning life initially used in their design. These dams play a central role in providing multiple benefits at USACE reservoirs related to water supply, hydropower, navigation, flood risk management, recreation, and environmental stewardship. Most federal reservoir storage projects are in need of substantial recapitalization and updates to their operating plans. Further, changing trends such as population growth, drought, inland and coastal flooding, and habitat loss intensify competing water demands. These competing demands require careful tradeoffs and cooperation in order to balance multiple uses under future conditions.
High Hazard Dams
The American Society of Civil Engineers (ASCE) completed an infrastructure report in 2017 that highlights the issues endemic to the Southwest Division's dams. The number of dams that are considered "high hazard" and are lacking regular maintenance and inspections are growing. Couple this finding the reality of decreasing funds for major flood reduction projects, long timelines, and complex planning, designing, and construction of new dams makes the problem a real one with no easy short-term solution.
Inadequate maintenance only makes the situation worse. With the increase in populations and continued urbanization of the areas downstream of USACE dams makes the threat of a major dam failure a significant one. But the problems aren't just the possible failure of dam hardware or superstructure. Most of the equipment that we depend on to generate hydropower to supplement the nation's electrical grid is just as old as the dams that they live inside. This is massive, complex hardware that was originally built by a generation of men and women that have passed into history. Rehabilitation work and ongoing maintenance and replacement of hard to find parts are issues that will be ongoing.
How does this affect Civil Works planning?
The state of USACE Civil Works like dams, reservoirs, and inland waterways, have a lasting impact on the communities that are served by them. While reservoirs might have been built for flood risk mitigation and water supply, the reality for most USACE reservoirs is that they are also incredibly beautiful natural ecosystems that attract tourists, homeowners, and businesses. Entire economies depend on the recreation business that springs up around the reservoirs as well as down stream along the rivers that these massive bodies of water are responsible for impounding. Higher water levels due to extreme weather are compounded by reservoirs that are filling with sediment impacting the available water storage capability of the reservoir. These higher water levels can flood private property, and make recreation more difficult as boat docks are submerged and Marinas are unable to operate at peak efficiency. Campgrounds must be closed due to non-maintenance or high water, and hydropower generation opportunities are often lost as generators fail and need expensive and hard to source parts for repair.
All of these different water uses are entangled with the state of the reservoir and the dams that created them. Water users such as farms and agribusiness that exist downstream of reservoirs are affected by how water is managed. The optimal conditions for these users may be different or in direct competition to recreation users on the lake or on the rivers that flow below the dams. All the while, water must be managed for quantity and quality and kept in balance for all of the reservoirs authorized uses. A failure of the dam's generator or gate hardware can create situations where water levels are kept abnormally high, impacting downstream water users and reservoir users in different ways. On larger inland waterways such as the McClellan-Kerr Arkansas River Navigation System (MKARNS), the need to maintain channel depth along the navigation channel and ensure the locks at each of the dams along the river are operating correctly are vital to not only the health of the river system, but also the health of the national economy. This means that scheduled maintenance must be done - some of which requires a complete dewatering of the lock mechanism - which can bring navigation on that section of the river to a temporary halt. Dredging to maintain channel depth is an ongoing effort that can be compounded in difficulty and time during periods of extreme weather or drought. While the kinds of work required and the effects on the river, the navigation industry, and private citizens that live along the river are all different and important.
IWRM and the Civil Works Strategic Plan seek to understand how all of the associated users are impacted - which will ensure that USACE and its partners can not only manage the water, but also ensure that vital maintenance and ongoing work are completed with minimal impacts to water users, businesses, and the environment.