Commentary
The Natural World
G. Tracy Mehan, III, former assistant administrator for Water at the U.S. Environmental Protection Agency, spoke before the Subcommittee on Water Resources and Environment of the House Committee on Transportation and Infrastructure. Mehan currently is an environmental consultant at The Cadmus Group, Inc.
The date was Feb. 4 and the topic was sustainable wastewater management.
Portions of his testimony, which he said reflect only his views, follow:
Let me start by describing the results from a study done in the area of source water protection (SWP), a concept derived from the 1996 amendments to the Safe Drinking Water Act but analogous to the concept of watershed protection under the Clean Water Act.
The Land
The idea behind SWP is to prevent contamination of drinking water supplies as part of a multibarrier approach which includes treatment. Increasingly, land conservation is seen as a fundamental part of source water protection. In fact, funds for land purchases can be obtained from the State Revolving Loan Funds for drinking water.
A study of 27 water suppliers conducted by the Trust for Public Land (TPL) and the
American Water Works Association (AWWA) in 2002 found that more forest cover in a
watershed results in lower treatment costs. For every 10 percent increase in forest cover
in the source area, treatment and chemical costs decreased approximately 20 percent.
Almost 50 to 55 percent of the variation in treatment costs can be explained by the percentage of forest cover in the source area.
In other words, the natural infrastructure, if you will, is a least-cost approach to protecting water quality that can generate multiple benefits such as habitat, carbon sequestration, and aesthetics. Utilizing such green or natural infrastructure means less
hard or gray infrastructure and reduced energy intensity, too.
We are seeing a similar trend in the realm of waste and stormwater management in more and more utilities and communities across the country. This is especially true with
respect to “urban wet weather” issues, a constellation of problems including combined
sewer overflows (CSOs), stormwater runoff, and conventional point-source or end-of-the-pipe discharges. More and more, they are addressing these challenges through a watershed approach which employs green or nonstructural approaches in tandem with traditional hard or gray infrastructure.
At the heart of these urban wet weather problems is the degree of imperviousness or hardening of the landscape throughout the watershed with a concomitant disruption to the natural flow regime. Roads, sidewalks, parking lots, roofs, and tightly compacted
building sites allow water to run off, carrying with it pollution into nearby streams and
rivers while also elevating water temperatures and increasing the velocity of the flow which scours stream and destroys biological diversity. The resulting condition is sometimes called the “urban stream syndrome.”
Low Impact Development
In cities such as Philadelphia, Chicago, Portland (Ore.) and Milwaukee, water managers are trying to implement green infrastructure solutions or low-impact development (LID) practices. A number of these techniques are well known … such as green
roofs, rain barrels, rain gardens, vegetated curb extensions, porous pavement, urban reforestation, and even constructed or restored wetlands or wet meadows. The aim of
these practices is to retain water on site, allowing for infiltration and evapotranspiration,
thereby reducing runoff and allowing for removal of unwanted pollutants.
In fact, Portland has actually incorporated LID solutions into its long-term control plan
for addressing its CSO issues. Unfortunately, this may be the only instance where LID
practices have been incorporated into the formal regulatory structure. EPA, specifically
the Offices of Water (OW) and Enforcement and Compliance Assistance (OECA) should
continue to facilitate the incorporation of the green solutions into CSO permits, not just consent decrees. Our understanding and knowledge of these techniques are getting better every day. It is time to incorporate them into the fabric our regulatory programs.
The Milwaukee Metropolitan Sewerage District is working with the Conservation Foundation, a national land conservancy, to purchase and restore 1,800 acres of floodplain area to date. This is both to meet the district’s flood plain management responsibilities, but also to ameliorate its CSO and stormwater problems.
Recently, the National Research Council of the National Academies released a landmark
study on the nation’s stormwater program in which it recommended managing stormwater on a watershed basis and using water flow as the common metric of regulation, as opposed to a pollutant by pollutant scheme. Such an approach could
include multiple agencies or jurisdictions with stormwater responsibilities in a given basin. Indeed, EPA has already promulgated guidance on watershed-based permitting that allows for a comprehensive, watershed approach, which could fold in all urban wet
weather issues if the permitted entities wanted to do so, and the federal and state
regulators gave their approval.
Both federal and state regulators need to encourage and facilitate such holistic and cost-effective steps to managing urban wet weather issues so as to reduce reliance on gray
solutions and encourage greener ones that are less costly and generate multiple environmental benefits.
State Clean Water Revolving Loan Funds should also begin to recognize and reward the efficacy of green or LID techniques in dealing with urban wet weather issues. A few states are starting to recognize the cost-effectiveness and multiple benefits of these approaches.
The goal of sustainable wastewater management also requires that we begin to pay greater attention to the nexus or inter-relationship between water, energy, and greenhouse gas (GHG) emissions. Clearly, a shift to green infrastructure or LID is in line with this goal. It is cheaper, less energy intensive, and has the potential even to promote biological
sequestration of carbon and mitigate urban heat island effects.
Renewable Energy
Global pressures on energy prices and environmental concerns have moved the issue of energy management to the top of the agenda for all utilities, especially wastewater and water systems. The water sector is estimated to consume 3 percent of the total electricity generated by the U.S. electric power industry. Energy is also used in individual homes to access water and wastewater services. And in some areas of the country, where water must be transported over large distances with daunting topography, the percentage is certainly higher. Finally, some experts are predicting that energy consumption at water and wastewater utilities will grow by more than 20 percent in the next 15 years. Whether it be capturing and reusing methane from a wastewater system or adopting various renewable energy sources, the water industry continues to embrace energy management as a key pillar of sustainable water and wastewater management.
Recently, the Oregon Association of Clean Water Agencies (ACWA) issued a new report
documenting how two wastewater treatment plants can become energy independent.
Funded by the Energy Trust of Oregon, Gresham and Corvallis, Ore., were able to take
steps to optimize energy efficiency and use renewable resources. Again, this report shows that many treatment plants can generate a substantial portion of their power by using methane gas. Gresham’s use of methane gas to generate clean power cut costs by $240,000 annually. It also purchases 17 percent of its electricity from wind farms.
Given the rise of carbon cap-and-trade programs on the West Coast and in the Northeast,
as well as the possibility of a similar federal program coming on line, there may be opportunities for water and wastewater utilities to participate in emerging carbon markets. Imagine a wastewater system selling carbon credits generated by its methane capture program. What if a number of drinking water utilities in any given watershed might pool resources to reforest a groundwater recharge area? In the process, they may be able to demonstrate substantial biological sequestration of carbon to participate in these new markets. If water and wastewater utilities are able to generate an income stream from their participation in a new carbon or GHG market, that would enhance their economic and environmental sustainability simultaneously.
This is not your parents’ water or wastewater sector! Green infrastructure now
supplements gray infrastructure. The land and water interface requires that it be managed on a watershed scale. Finally, the nexus between energy, water, and carbon necessitates new approaches which recognize the importance of this interrelationship.
Policy, regulation and financing should support these shifts in water management and
allow for the implementation of those practices that deliver the most cost-effective solutions to the broad array of environmental challenges facing us now, some 36 years after passage of the Clean Water Act.
To contact Mehan, phone 703.247.6106 or send e-mail to gmehan@cadmusgroup.com.