| Watershed Restoration Planning Guidebook
Watershed Restoration Planning Guidebook
Purpose of this Guidebook
North Carolina is known for its pristine waters and beautiful beaches. Yet, 2,446,218 acres of marshes, sounds and lakes in the state, and 2,222,694 acres of coastal shellfish and swimming waters are listed as legally impaired on the EPA 303(d) list due to bacteria in runoff pollution. That accounts for over 3,822 square miles of impaired state waters and 3,573 square miles of coastal waters that are closed for their designated uses for swimming or the harvest of shellfish, and in need of restoration. This problem is not unique to N.C. and many coastal communities around the United States struggle with the same coastal water quality impairments.
The purpose of this guidebook is to provide clear and detailed guidance for the development of a watershed management plan that aims to replicate the pre-impairment surface water hydrology and thereby improves coastal water quality.
Use of Best Management Practices (BMPs) for stormwater runoff reduction to decrease pollutant loads in coastal watersheds is the focus of this guidebook. Stormwater runoff volume has increased since naturally vegetated landscapes have been made more impervious by land use changes. With an increase in surface runoff volume comes an increase in the amount of bacteria, nutrients, and other pollutants carried into coastal waters. Restoring the natural hydrology can reduce bacteria and pollutant loads, thereby improving coastal water quality.
The methods and philosophy presented in this guidebook were initially developed by the N.C. Coastal Federation to complete and implement three watershed management plans (White Oak River, Lockwood Folly River, and Bradley and Hewlett’s Creek) and have been further refined by testing the methodology in three other subwatersheds (Howe Creek, Williston Creek, and Mattamuskeet Drainage Association).
A watershed management plan is used to protect and restore water quality. This guidebook provides detailed instruction for coastal watershed managers to devise a management plan that will:
- Establish long-term goals for improving or protecting coastal waters and subwatersheds;
- Develop strategies to accomplish these goals;
- Ensure stakeholder participation;
- Identify and analyze pollutant characteristics;
- Measure water quality goals; and
- Result in management measures to meet the desired objectives.
How to Use Your Plan in Lieu of a TMDL
When surface waters no longer comply with assigned water quality classifications and standards, the federal Clean Water Act (CWA) mandates that steps be taken to remove the water quality impairment and restore water quality to acceptable levels. This normally involves conducting a Total Maximum Daily Load (TMDL) study to determine how much pollutant loads should be reduced to restore water quality. Once the TMDL is completed, then a watershed restoration plan is devised to accomplish the desired reductions in pollutant loads.
TMDL studies typically cost many thousands of dollars and can take several years to complete. For many coastal subwatersheds where pollution is caused by stormwater runoff and not discharges of industrial or domestic wastewater, scientific monitoring has shown repeatedly that altered watershed hydrology creates additional surface runoff that then washes bacteria into downstream coastal waters. This methodology allows managers to estimate how much additional surface runoff has been created as a result of hydrologic modifications, and establishes a numerical goal for how much runoff must be reduced to restore impaired water quality. This numerical volume reduction goal, which forms the basis for a watershed management plan, can serve in lieu of preparing a TMDL where there are ample water quality monitoring data and documentation of the relationships among: intensity of land uses, greater hydrologic modifications, and increasing bacteria levels.
The TMDLs and watershed management plans for the Lockwoods Folly and White Oak Rivers were approved by EPA and N.C. Department of Environment and Natural Resources (DENR). These plans provided guidance for the City of Wilmington to follow in developing the Bradley and Hewletts Creeks Watershed Management Plan, which was approved by the DENR to serve in lieu of a mandatory TMDL. This voluntary plan gives the city time to accomplish restoration efforts without facing a legal mandate from EPA. This guidebook provides step-by-step instructions for how to devise volume-based TMDLs and/or a watershed management plan. The methods outlined can be used to satisfy mandatory requirements in coastal watersheds for a TMDL, or to devise a watershed management plan that will serve as a voluntary effort to address water quality impairments.
Other Uses of this Guidebook
In areas where a TMDL assessment has already been completed or will be performed, a watershed management plan can complement restoration efforts. A watershed management plan can present strategies to control non-point source pollution that is not readily addressed through the TMDL process.
Plans developed according to this guidebook can also be effective in improving water quality in areas that are not considered legally impaired. These are areas where one or more uses for the water (e.g., shellfish or swimming) did not exist when the Antidegradation Policy pursuant to the federal Clean Water Act was established in 1975 (see Chapter 2). If waters are not legally impaired, there may be no state or federal requirements to improve water quality. However, a community may want to establish or regain uses of these waters and may do so by constructing a plan according to the guidance provided herein.
How this Guide Compares to the EPA Watershed Handbook
Many elements of this guidebook were adapted from the EPA Handbook for Developing Watershed Plans to Restore and Protect Our Water. Similarities and differences include:
This guidebook concentrates specifically on coastal subwatersheds with swimming and shellfish water quality impairments.
This allows implementation of management strategies tailored to the differing land use patterns and natural hydrology of coastal area. By having a small project scope, in many cases even smaller than the 12-digit Hydrologic Unit Code (HUC) subwatersheds, planning efforts can become more focused and more easily implemented.
- Instead of attempting to eliminate sources of bacteria, the methods in this guidebook seek to reduce the transport of bacteria by reducing the volume of surface runoff.
Previous projects that tested these methods, including those on the White Oak River, Lockwood Folly River, and Hewletts and Bradley Creeks, show that one of the best ways to restore coastal water quality is to mimic natural hydrology and to reduce the overall rate and volume of stormwater runoff. This technique reduces the overall pollutant loads deposited into watersheds. This guide helps set volume reduction goals and develop management strategies for meeting those goals in order to improve water quality. This is effective because impairment of waters is predominantly due to the alteration of hydrology within these very small watersheds.
Following the methodology outlined in this guidebook will ensure your plan incorporates all nine elements of a watershed management plan as required by EPA as necessary to qualify for 319 funding that is used to restore impaired waters.
Incorporation of these nine elements will increase the likelihood that your plan can serve in lieu of a TMDL. The EPA’s nine minimum elements will be discussed frequently throughout this guidebook, and include:
- Identification of causes of impairment and pollutant sources or groups of similar sources that need to be controlled to achieve needed load reductions, and any other goals identified in the watershed plan.
- An estimate of the load reductions expected from management measures.
- A description of the nonpoint source management measures that will need to be implemented to achieve load reductions, and a description of the critical areas in which those measures will be needed to implement this plan.
- Estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon to implement this plan.
- An information and education component used to enhance public understanding of the project and encourage their early and continued participation in selecting, designing, and implementing the nonpoint source management measures that will be implemented.
- Schedule for implementing the nonpoint source management measures identified in this plan that is reasonably expeditious.
- A description of interim measurable milestones for determining whether nonpoint source management measures or other control actions are being implemented.
- A set of criteria that can be used to determine whether load reductions are being achieved over time and substantial progress is being made toward attaining water quality standards.
- A monitoring component to evaluate the effectiveness of the implementation efforts over time, measured against the established criteria.
Purpose of Targeting Small Coastal Watersheds
Although this guidebook is designed to be adaptable for use in any coastal watershed, it focuses on devising management plans for watersheds that flow directly into shellfish or swimming waters. These are small drainage areas that are usually much smaller than the 12-digit HUC watersheds that are typically used in watershed planning. Planning on this very small watershed scale allows local leaders to influence change in their area through feasible community-level actions. These small-scale and frequently low-cost actions can have significant positive benefits for the community, including the reopening of closed shellfish waters and a reduction in the frequency of swimming advisories issued for local waters.
Adapting this Guidebook to Your Watershed
While this guidebook is tailored to N.C. coastal subwatersheds, it can easily be used to create a watershed management plan in any coastal watershed throughout the nation where impairments are the result of polluted runoff. The partners and agencies mentioned in this document may not be directly relevant to states outside of N.C., but they can act as suggestions for where to look to find similar information.
There are a handful of state-specific guidebooks that include these elements, so be sure to check if your state already has a planning guidebook. This guidebook provides N.C. specific resources, organizations, and data sources to ease the planning process. A successful and effective watershed restoration plan will include, at minimum, the EPA’s nine components but should also include the critical other steps outline in the nine chapters. It is important to revisit the steps throughout the planning, implementation, and evaluation process, always with the intent of improving the project and achieving restoration goals.
Extensive Water Quality Monitoring Eases Planning Efforts in Coastal N.C.
In N.C., the Shellfish Sanitation and Recreational Water Quality Section (Shellfish Sanitation) of the Division of Marine Fisheries (DMF) is responsible for monitoring the bacteria levels in coastal waters and has the authority to close waters to shellfishing and issue swimming advisories when bacterial levels are unacceptable. This Section monitors bacterial water quality conditions at over a thousand of stations for shellfishing and 240 stations for swimming. In addition, every three years Section staff walk the entire shoreline of shellfish growing areas to document current and potential pollution sources during their shoreline survey. The data resources available on the N.C. coast give managers and planners excellent information to affect change without the need for extensive data collection and monitoring.
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| Watershed Restoration Planning Guidebook