The Lake Maumelle watershed

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1 Source Water Protection Central Arkansas: Programs & Practices Martin Maner, PE and Trevor Clements Implementing Adaptive Management in Central Arkansas Introduction The Lake Maumelle watershed in central Arkansas drains approximately 137 square miles (88,000 acres) and includes portions of Perry, Saline, and Pulaski counties, as well as the City of Little Rock s extraterritorial jurisdiction (Figure 1). Central Arkansas Water (CAW) owns and operates Lake Maumelle (Figure 2) as one of two principle water supplies for Little Rock and 16 other cities and communities in the region. Currently, CAW serves approximately 400,000 people with an estimated growth to 575,000 by Lake Maumelle was built in the late 1950s as a water supply lake at an estimated cost of $37 million (in 2010 dollars). Today it would cost far more to replace this high-quality supply. Lake Maumelle has also become a place for recreation, a sanctuary for wildlife and waterfowl, and a place of serenity for the community. Approximately 77 percent of the watershed is forest, 4 percent pasture, 6 percent clear-cuts, and 10 percent water. The balance is in highway rights of way, roads, streets, and private yards. Land use changes are expected in each of the watershed s jurisdictions. Approximately 46,500 acres are in private ownership and potentially developable. The value of the resource and the potential land use changes raised concerns about the protection of Lake Maumelle and the health of those drinking its water. A task group for watershed management convened in 2004 recommended that CAW develop and implement a watershed management plan that adequately addresses the scientific, social, political, recreational, aesthetic, and economic factors influencing land use Figure 1. Location map of Lake Maumelle watershed in Central Arkansas. decisions in the Lake Maumelle basin. Although conducted before the guidance was developed, the plan provides an excellent example of the ANSI/ AWWA G300 Source Water Protection recommended steps including identify source water protection goals, produce action plans, implement the plans, and evaluate effectiveness. Building the Framework In 2005 CAW initiated a watershed study to develop a comprehensive watershed management plan. CAW invited community groups to appoint representatives to a 22-member policy advisory council (PAC) to guide development of the plan. The PAC included CAW as a stakeholder as well as private landowners, local government representatives, business and environmental groups, and recreational and citizen groups. A panel of 14 technical resource advisors from academia, agencies, consultants, and CAW was also convened to provide input on and review of technical issues throughout the planning process. In addition to the 18 Fall 2011 / LAKELINE

2 Figure 2. Lake Maumelle, Arkansas is one of two water supply lakes for Central Arkansas Water. Photo by Dennis Yarbro, Central Arkansas Water. frequent policy and technical council meetings, multiple public meetings were held at four different times to share information and provide opportunity for anyone interested to participate. For the first phase of the project, existing information was compiled and reviewed to develop an understanding of watershed and lake conditions, geomorphic reconnaissance of the watershed was performed, and issues that needed to be addressed were highlighted. Results were presented to the PAC and a technical advisory committee (TAC). Through a facilitated process, the PAC endorsed watershed management goals and objectives. During phase 2, a linked watershed and lake response modeling framework was set up and calibrated to support indicator evaluation. A baseline modeling analysis was performed that compared existing conditions to future buildout conditions assuming no changes in management. Results were compared with established targets and used to identify focus areas and determine the most promising management options to test. Other tools developed during phase 2 included a cost evaluation tool and a site-scale model for analyzing the impacts of alternative development designs on pollutant loading. Phase 3 of the process involved initial watershed management plan development. Ideas were presented in February 2006 at public meetings held for watershed property owners and CAW ratepayers. Based on public feedback, conceptual ideas were turned into specific management alternatives for detailed evaluation. Results of the alternatives evaluations were shared with PAC members and the public at several meetings and workshops held in July A draft plan was reviewed by stakeholders, local government planning boards and elected officials, and the CAW Board in late Based on the technical analysis and stakeholder input for the draft management options, a refined version of the Lake Maumelle Watershed Management Plan (Figure 3) was approved by CAW Board of Commissioners in May The adopted plan focuses on the following areas: New development (runoff during construction; post construction runoff; wastewater), improvement, and maintenance of existing roads Spill containment Forestry practices Lake management Livestock management Good household practices Land acquisition Emphasis is placed on controlling sediment, phosphorus, total organic carbon (TOC), and pathogen loading from the watershed. The largest potential sources are expected from new development and the associated domestic wastewater. The Plan recommends local Watershed Protection Ordinances or Subdivision Ordinances be adopted for new development, as well as local Sedimentation and Erosion Control Ordinances for land disturbance activities in the watershed. The most important recommendation in the Plan was state prohibition of direct surface discharges of wastewater in the watershed. The Plan recommends a responsible management entity (RME) be established to manage design, Figure 3. The Management Plan provides a guide for stakeholders for watershed protection. Fall 2011 / LAKELINE 19

3 construction, operation, and maintenance of non-discharging wastewater systems or to oversee pumping of wastewater out of the watershed. Finally, the Plan provides flexibility to address concerns of current watershed residents. Exemptions to proposed ordinance requirements are allowed such that existing landowners can construct additions to their homes and businesses and create small subdivisions for family members that would not have to comply. To provide these exemptions and meet water quality targets, the Plan calls for CAW to acquire 1,500 acres of conservation land in the watershed. Programs and Practices in Place to Implement the Recommendations of the Plan The major components of the CAW Implementation Plan include prohibition of point source discharges, water quality monitoring, land management, land acquisition, and a spill response plan. The details of these components are summarized below. Prohibition of Point Source Dischargers within the Watershed The number one priority was the effort to prohibit the surface discharge of wastewater (excluding storm water discharges) in the watershed of Lake Maumelle. This got underway at CAW in July of The intent was to prohibit the surface discharge of wastewater as covered under the state s NPDES program. Currently, there are no surface wastewater dischargers in the watershed. The ban would not apply only to subsurface systems such as septic tanks, drip irrigation, etc. Working with the state regulatory agency and other concerned parties to get the ban implemented took nearly three years, but it was finally approved. Prohibition of surface discharge of sewage to the watershed was achieved by modifying Arkansas Pollution Control and Ecology Commission Regulation #6 (authorizes state implementation of the EPA NPDES program). The Commission passed the prohibition unanimously at its May 2010 meeting. This prohibition means Central Arkansas will continue to have good water quality in Lake Maumelle and CAW water will be free of pharmaceuticals, personal care products and other constituents of human sewage, and other wastewater products. Pollutant Loading Performance Standards for New Development CAW has worked closely with Pulaski County, the most populated jurisdiction that lies in part within the Lake Maumelle Watershed. In 2009 the county passed an ordinance requiring water quality protective measures for subdivision development within the watershed portion of the county. Sitespecific unit area pollutant loading rates (i.e., stormwater management performance standards for new development) established by the Plan for Critical Areas of the watershed as shown in Figure 4 were adopted. The standards apply to post-construction loads of sediment, phosphorus, and TOC. By late summer of 2009 Pulaski County set to work on developing a storm Figure 4. Map showing critical management area boundaries. 20 Fall 2011 / LAKELINE

4 water design manual and site evaluation tool (SET) for the Lake Maumelle watershed portion of the County. The manual provided guidance to landowners and developers, and a means for checking development designs for compliance with the standards. The design manual and SET tool (available online at ar.us/planning6.shtml) were adopted by the county in the summer of This tool, along with the subdivision ordinance, is now being used to ensure compliance before a development design recommendation is made to the County Planning Board. Pulaski County is also developing a comprehensive land use plan for the Lake Maumelle watershed portion of the county. The final draft of the plan was just completed and presented to the public as of this writing (May - June 2011). Monitoring and Assessment Framework to Support Adaptive Management Long-term monitoring and assessment framework to support technical analysis and plan performance evaluation is necessary so that adjustments can be made as needed. Watershed management is not a one-time planning event. Rather, the communities must be in a position to rapidly respond to the dynamics in the watershed. The reality is that things change: land use, climate patterns, management practices, economies, and politics all can change significantly within short periods of time. Maintaining a capability to assess the impacts of changes as they occur provides watershed managers with the technical basis to make informed decisions. CAW has implemented an aerial monitoring program to help track land use changes, a water quality monitoring program to provide information at discrete points in time and location, and a modeling framework to extrapolate information to all points in the watershed and lake and to predict responses to subsequent proposed management measures. information on land use changes through time. In addition, to better determine which tributaries may be contributing significant storm inputs, CAW has an on call contract for aerial photos that are taken following major storm events. Thus, they can determine which tributaries are delivering the most turbid water. Figure 5 provides an example of such a photograph. Finally, CAW has contracted and received a high-resolution land cover database from the 2009 photos. These provide land cover in seven categories at quarter-acre resolution. Water Quality Monitoring CAW has a strong source water quality monitoring program contracted through the U.S. Geological Survey (USGS) for Lake Maumelle and a secondary water supply, Lake Winona that lies within the Ouachita National Forest. The annual budget for this program is roughly $425K. Streams entering Lake Maumelle other than the Maumelle River may not flow on a consistent basis, but provide significant flows and pollutant loads during storm events. Storm event samples have been collected at up to seven sites in the watershed. In addition, there are five lake monitoring sites within Lake Maumelle. This sampling network provides objective information regarding changes that may occur over time as land use changes. Monthly samples are collected at the five lake stations and two Maumelle River sites. Additionally, there are two real-time water quality monitoring stations, one on the Maumelle River and one at the upper end of Lake Maumelle. Samples constituents include nutrients, total and dissolved organic carbon, turbidity, total suspended sediment, minerals, heavy metals, and pesticides. Sampling and analysis is also periodically conducted for pharmaceuticals and personal care products. Continuous flow gauging and water quality monitoring over long periods of time is essential to evaluate watershed pollutant loading, as well as hydrologic changes. USGS currently operates eight continuous flow or reservoir elevation gauges in the watershed. Monitoring sites are shown in Figure 6. Results of monitoring and data collection are analyzed, evaluated, and fed back into the decision-making process for adaptive management. This occurs in a variety of ways, including relating the data to the land cover changes, and updating the watershed and lake models every five or ten years as necessary. The real-time data for turbidity, temperature, and dissolved oxygen are evaluated on a daily basis and can be used to provide to treatment plant operators if there are concerns regarding high turbidity, or lake turn-over events are likely to occur. Aerial Monitoring CAW contracted for and received one-foot resolution color and color infrared photos for the Lake Maumelle Watershed, taken in February Aerial photos going back to 2002 are also available. The photos provide Figure 5. Aerial photograph of Lake Maumelle following a major storm event. Fall 2011 / LAKELINE 21

5 to engage stakeholders to support implementation including best practices for water quality protection. Figure 6. Location of USGS gauging stations. Watershed management staff, working with USGS staff work together to evaluate long term water quality data and associated long-term trends. Annual reports are produced by the USGS for CAW and these summaries focus on the appropriate water quality targets. Land Management A forest management plan is being developed for the 9,400 acres that CAW owns around the lake. The plan will focus on management for prevention of catastrophic fires, habitat improvement for non-game species as well as game species, and management of the land to protect water quality in the lake. Land Acquisition Central Arkansas Water is acquiring additional land within the watershed that has potential for future development. The Plan recommended acquiring 1,500 acres within ten years. To date CAW has acquired 1,795 acres. More purchases are planned. Management plans are developed for the land once it is acquired. Total CAW owned land is currently at 9,433 acres. Spill Response Plan CAW has a spill response plan for Lake Maumelle that provides contact numbers, anticipated flow paths, and the necessary actions required in case of a spill on one of the three transportation corridors around the lake. Mock field drills have also been conducted to minimize unforeseen problems. Watershed Management Administration Institutional capacity has been added at CAW to oversee ongoing watershed management plan implementation. CAW maintains a watershed director, a watershed administrator (engineering position to oversee new development plan reviews, construction and postconstruction stormwater management inspections, and wastewater management), and a part-time stewardship coordinator. The latter position facilitates the Lake Maumelle Watershed Stewardship Council, the body of appointed elected officials and landowner representatives established to carry on the policy making for the watershed. The coordinator also conducts public outreach Summary Source watershed protection in Central Arkansas has been greatly enhanced for Lake Maumelle through investment by CAW and its partners in the region. Development and application of a technical assessment framework (a linked watershed and lake response modeling framework supported by monitoring), adoption of goals and objectives, establishment of indicators and targets for achieving the goals and objectives, generation of a watershed management plan and an Implementation Strategy, and the building of institutional capacity provide an adaptive management framework for sustaining watershed protection long into the future. Accomplishments in implementation (ordinances, design manual and SET, land management plan, hazardous waste spill response plan, and land acquisition) demonstrate the effectiveness of a comprehensive approach to source water protection. Martin Maner, PE, is the Watershed Director for Central Arkansas Water, 221 East Capital Ave, Little Rock, AR Contact: (501) or Martin.Maner@CArkW. com. Trevor Clements, MEM, is the Director of Water Resources and National Watershed Management Practice Leader for Tetra Tech, P.O. Box 14409, Research Triangle Park, NC Contact: (919) extension 100 or trevor.clements@tetratech.com. x 22 Fall 2011 / LAKELINE