Water Sector Resilience & Redundancy

With a rich history of coordinated water supply planning, the National Capital Region has been conducting regional workshops and creating new study results to enhance its ability to address the region’s water needs during a crisis. The resulting information will spur further discussion and assessment of drinking water system alternatives for the region.

President Barack Obama issued Presidential Policy Directive-21: Critical Infrastructure Security and Resilience in February 2013, thus establishing the “policy of the United States to strengthen the security and resilience of its critical infrastructure against both physical and cyber threats.” In particular, the National Infrastructure Advisory Council hasentified the water, energy, transportation, and communications sectors as “lifeline sectors” that should be top priorities for strengthening resilience. Of those sectors, various studies such as the Regional Catastrophic Preparedness Grant Program Supply Chain Resilience Project have found that a failure of the water sector (drinking water or wastewater) could prove to have particularly catastrophic consequences.

Brief History of D.C.’s Water Infrastructure 

In the Metropolitan Washington Region, water-sector issues have been addressed for decades. The Metropolitan Washington Council of Governments (MWCOG) – comprised of 300 elected officials from 22 local governments, the Maryland and Virginia state legislatures, and U.S. Congress – has worked since its founding in 1957 to address the management and protection of the drinking water supply for the region, including the resources of the Potomac River. The Chesapeake Bay and Water Resources Policy Committee addresses regional water quality issues for MWCOG. The Interstate Commission on the Potomac River Basin (ICPRB), authorized by an Act of Congress in 1940, is an advisory, interstate compact agency of the Potomac basin states of Maryland, Pennsylvania, Virginia, West Virginia, and the District of Columbia that, among other items, addresses water supply issues in the Metropolitan Washington Region.

In July 1982, the Baltimore District of the U.S. Army Corps of Engineers, Fairfax Water, the Washington Suburban Sanitary Commission, the District of Columbia, and the ICPRB signed a Water Supply Coordination Agreement to direct their operations during drought. ICPRB’s Section for Cooperative Water Supply Operations on the Potomac was designated by the Water Supply Coordination Agreement to be responsible for coordination of water resources during times of low flow to keep the off-Potomac reservoir resources balanced while meeting environmental requirements and municipal demands for water. The off-Potomac resources include Jennings Randolph, Savage, Little Seneca, Occoquan, and Patuxent reservoirs. Included as part of the Water Supply Coordination Agreement are reliability assessments to be completed every five years. ICPRB completed the most recent assessment in 2015.

In 1999, MWCOG’s Board of Directors established a Task Force on Regional Water Supply Issues to: review regional water systems; examine the roles of the water utilities, government, and others; andentify key issues in long-term water supply planning and drought management. The Task Force work led to significant revisions to the regional Water Supply Emergency Plan and the adoption of a regional Drought Emergency Plan. For decades, regional agreements such as the Water Supply Coordination Agreement, the Low Flow Allocation Agreement of 1978 (and subsequent modifications), and the regional Drought Emergency Plan have been used to successfully manage the Metropolitan Washington Region’s water supply as a system.

New Study & Series of Workshops

Consistent with the region’s longstanding record of effective and coordinated regional water supply planning – which promotes the sharing of benefits, risks, and resource costs – a regional water system redundancy study is presently underway, building on a previous 2007 study. The main purpose of this regional study is to investigate options for improving water supply resilience and security through assessment of adding supplemental water storage capacity, system interconnections, and other actions. Funding to carry out the study was made available from a Federal Emergency Management Agency Urban Area Security Initiative grant. Major study participants include MWCOG, ICPRB, Washington Suburban Sanitary Commission, Fairfax Water, the Washington Aqueduct, DC Water, several other local governments/utilities, and Black & Veatch, a consultant engaged to perform the study.

Working with MWCOG staff and other project partners, Black & Veatch scheduled five workshops, between June 2015 and March 2016, with key regional water supply utilities in the National Capital Region. The workshops were essential to conducting the analysis by satisfying the general goals of the project and ensuring a working dialogue among utilities, MWCOG, and Black & Veatch. The operation of existing interconnections and water-sharing arrangements between utilities was discussed, as well as opportunities to improve the region’s capability to move water across individual geographic system boundaries – as would be required in a regional emergency situation. Each workshop focused on reaching group agreement on important steps in the analysis. The goals of the workshops were to:

• Establish the minimum level of regional water supply service acceptable during an emergency, based on expected customer demand during planning year 2040;

• Define failure events that could result in water supply outages by exceeding the region’s system storage capability;

• Quantify the probability of occurrence of failure events, duration of outages, and number of customers affected; and

• Identify and define (for each failure type) potential infrastructure improvements to mitigate water supply outages.

A fifth workshop was held in March 2016 to review outputs from a risk model that synthesized the failure conditions, outage assumptions, and potential combinations of infrastructure improvements. A business case analysis of the combinations of improvements provided insight to the benefits and costs of improvements, and accounted for water system synergies and dependencies. The methodology allowed the infrastructure improvements to be evaluated with respect to regional system benefits, and provided a cost-efficiency ranking relative to projects and costs of mitigating the group ofentified risks.

The ongoing National Capital Region water system resilience and redundancy study is scheduled for completion by 31 May 2016. During April and May 2016, regional water utilities and other stakeholders will continue to assess potential combinations of infrastructure improvements. Some of the information that will be developed before the end of May includes:

• Identification of daily operational benefits associated with specific projects that were not considered in the initial benefit-cost ratios;

• A sensitivity analysis to assess how factors like the frequency of outages might change the priority rankings; and

• A breakdown of estimated costs and benefits by jurisdiction.

When completed, the resulting information will provide the National Capital Region with a foundation for ongoing regional discussions of priorities, timing, and funding of infrastructure to enhance the region’s ability to adapt and respond to customer water needs during regional emergencies.