Water Quality Research Needs in Transportation

Paper presented before the Transportation Research Board Committee on Hydraulics, Hydrology, and Water Quality

Fred G. Bank
Environmental Quality Branch
Federal Highway Administration
Washington, D.C.

January 1993

Introduction

In the early 1970's a growing awareness of the potential threat to water resources by highway construction and operation emphasized a need to identify and quantify water quality impacts. With the passage of the National Environmental Policy Act and the Clean Water Act of 1972, as amended, Federal decision takers were to be accountable for activities having the potential to impact features of the natural environment, in particular water quality.

The planning for and implementation of highway systems can interact with the nation's water resources in numerous ways. Since most highway sections lie within or cross a watershed, all phases of project development have the potential for impacting both surface and underground water resources. Highway project planning, location, and design activities can greatly influence future uses of water resources in localities by determining patterns of growth, secondary development, and water supply distribution. Construction and maintenance activities can have direct impacts to both supply and water quality characteristics of the project area. A variety of impacts are possible, ranging from the erosion of disturbed soils to the chemical pollutants associated with highway maintenance practices. Finally, the operation of highways open to traffic cause numerous other potential pollution sources created by the chemical and biological contaminants present in roadway stormwater runoff.

Significance

Under policies of the Federal Highway Administration (FHWA), environmental protection and enhancement are high-priority program areas that stresses the evaluation of highway-related water quality impacts; avoiding, mitigating, or managing such impacts; and coordinating with other agencies to ensure that Federal environmental policies are placed in perspective with other primary highway missions.

Past research sponsored by the FHWA identified and measured these various pollution sources and developed techniques to lessen their impact on water resources. This information has been used by project development personnel to plan and implement highway improvements. The improved understanding of pollution sources and solutions to water quality problems has greatly increased the States' ability to plan and construct highway improvements having minimal effects on water quality.

Research Activities

Water Quality Synthesis

This research effort will combine the results of past water quality research on highway runoff and water resources. This will include computer software developed in conjunction with runoff predictive methodologies. The effort will produce a single report that should be immediately useful to highway designers and environmental personnel to determine potential problems and formulate mitigation solutions.

Evaluation of Water Quality Monitoring Equipment Used to Measure the Constituents of Highway Stormwater Runoff

This effort will study the sampling of highway stormwater runoff with commercially available, "off-the-shelf" water quality monitoring equipment. A guidance document will be prepared that describes the benefits and problems associated with various types of equipment. The results of the effort may lead to improvements in sampling equipment specifically adapted to highway drainage situations.

Update Existing Baseline Data Used to Predict Highway Stormwater Constituents and Loading Characteristics

This research will involve extensive monitoring and evaluation of highway stormwater runoff data gathered from various types of facilities and climatic regimes. The data will be used to validate or revise existing baseline figures used in the current predictive methodology. Based on the data gathered, the predictive model will likely have to be revised to reflect revised runoff constituent concentrations, receiving water loading estimations, and background pollutant levels.

Evaluate the Performance of Best Management Practices (BMPs) Used to Mitigate the Impacts of Highway Stormwater Pollutants on Receiving Waters

This research effort will collect and analyze data on the performance of established runoff-quality control devices at selected sites. The results of the data collection and analysis will provide guidelines on the effectiveness of various BMPs and a selection technique to match specific control measures with runoff water quality problems.

Determine the Potential for Impacts to Receiving Waters Caused by Highway Stormwater Runoff

This study will identify short and long term water quality effects on surface and groundwater receiving stormwater runoff from roadway surfaces. The most prevalent of the identified effects will be field monitored to provide quantified estimates of impact. These data will be used to develop a predictive method or methods for making impact predictions. Simplified decision tools to make reliable determinations of impact and possible mitigative actions will be the final result of the effort.

Develop an Assessment Methodology and Management Guidelines for Cumulative Water Quality Impacts of Highway Stormwater Runoff

This research will examine long term and additive effects of highway stormwater runoff on an area-wide or watershed basis. Watershed runoff impacts will be examined in various geographical regions around the country. The results of these examinations will be used to develop an assessment technique for prediction secondary and cumulative impacts of roadway runoff on area-wide water resources. Comprehensive Integrated Water Quality and Water Resource Management - This research will determine how to integrate highway planning, design, right-of-way, construction, operation, and maintenance issues with water resource protection in a watershed context. The results, when combined with the findings of the study on impacts to receiving waters, will be used to formulate management guidelines for runoff and pollution control that address area-wide water quality and quantity problems.

Benefits

• Predictive Methods and Techniques - More accurate and reliable water quality prediction software, assessment guidelines, and potential training materials and other reference literature.
• Mitigation and Enhancement - Effective and defensible methods for reducing the impact of stormwater runoff. This would include a comprehensive list of BMPs demonstrated to be successful in controlling stormwater runoff problems.
• Improved Project Planning and Development - The improved understanding of runoff impacts will increase our ability to plan and implement projects in full coordination with long-term, area-wide water quality improvement programs. Results may include measurable water quality improvements in certain areas.
• Improved Understanding of Background Water Quality Conditions - This will allow highway planners and environmental personnel to properly assess the contribution of highway improvements in the overall scheme of nonpoint source pollution. This knowledge will also greatly improve our confidence in planning and implementing project mitigation features.
• Latest Information on Water Quality Monitoring Equipment - Equipment specifically suited for use in highway runoff situations will be identified.

Supporting Research and Development Needed

• Development of improved methods, techniques, tools, models, and procedures to evaluate the water quality impacts of highway development and operation activities, particularly stormwater runoff and changes in hydrology.
• Identification and development of innovative best management practices, devices, and other mitigation measures.
• Development of expertise within FHWA and State transportation agencies which integrates highway water quality and stormwater issues with all water resource problems associated with highways, including hydraulic and hydrological concerns.
• Coordination with other agencies to ensure that Federal stormwater and nonpoint source pollution policies are incorporated into FHWA and State policies and procedures.

Questions and feedback should be directed to Marlys Osterhues (marlys.osterhues@dot.gov, 202-366-2052).