If Maine is to ensure the quality of its drinking water, mitigate hazards of flooding, and handle the effects of stormwater, it will have to make widespread use of cost-effective alternatives instead of relying on large and expensive infrastructure improvements.
That's one of the main conclusions of the new report,"An Assessment of the Economics of Natural and Built Infrastructure for Water Resources in Maine," from researchers at the Muskie School of Public Service at the University of Southern Maine.
Co-authors Charles Colgan, Damon Yakovleff, and Samuel Merrill state, "Historically, almost all water resource issues were addressed by building expensive new infrastructure." The co-authors conclude that "Maine's most essential resource" can be best managed through a combination of promoting the use of existing natural systems and constructing "lower-cost decentralized structures."
The need to pay increased attention to Maine’s water resources is driven in part by increasing costs to comply with federal laws today and in part by a changing climate. Current best estimates of climate change indicate that Maine will experience both more intense precipitation periods and periods of drought. Higher precipitation rates will increase the risks of flooding, while periods of drought will stress the supply of high-quality drinking water.
A cost-effective approach, researchers say, may be to invest more in the conservation of forests and wetlands, which have historically reduced flood damage and provided natural water filtration, and support improvements on built structures such as culverts that complement or support natural infrastructure. A study of the Portland Water District’s service area found that an investment of $44 million in buffers of land along rivers, lakes and streams, culvert upgrades, sustainable forest management and conservation of forested land could save over $110 million when compared to the cost of building a new filtration plant to treat drinking water. Similar savings could also be possible for other public water systems in Maine, such as Lewiston, Auburn, Bangor and Brewer.
“This report is a superbly researched and well-written development of the key benefits that natural areas provide for water management in Maine,” said Mark Anderson, senior instructor in resource economics and policy at the University of Maine’s School of Economics. “The report makes a compelling case that the benefits will often far exceed the costs.”
The report lays out the need for a tiered approach to upgrading culverts throughout the state. Culverts play a critical role in Maine’s transportation system, providing water passage and drainage beneath roads or other crossings. According to a recent report by the New England Environmental Finance Center, there are approximately 35,000 culverts in Maine, and a large percentage would not be able to accommodate expected increases in precipitation.
“When culverts fail, roads fail,” said Colgan. Road failures in the wake of the intense storms of 2005 and 2006 required the replacement of culverts throughout western and southern Maine, but current federal policy after disasters is to replace culverts with the same size as those that failed. Upgrading to culverts large enough to accommodate expected storm flows and to allow wildlife passage will cost more but reduce the likelihood of future failures while improving wildlife habitat at the same time.
The report also examines the effectiveness of stormwater management techniques designed to mimic the way natural areas work, such as street trees or rain gardens that can help treat stormwater run-off, or porous paving materials that allow stormwater to be absorbed by the ground. These techniques take pressure off of built systems for waste water, which is especially critical in highly developed areas in the state. Ten out of 11 municipal stormwater management programs in the Bangor area decreased their costs by using these low-impact, or diffused, systems.
Land conservation can also serve as a cost-efficient approach to managing Maine’s water resources. To gauge the impact that natural areas could have in flood damage protection and stormwater management, report authors created a simulation of risks in three York County watersheds: The Branch Brook/Merriland River, the Kennebunk River, and the Mousam River. They found that investing an estimated $15 million to conserve important natural areas in these watersheds could provide a benefit of more than $275 million in avoided flood damage costs over time.
In an analysis completed for this report, scientists at The Nature Conservancy estimated that 825,000 acres of natural land throughout Maine have the potential to either help maintain drinking water quality or provide flood control benefits. Using cost estimates based on Maine’s land conservation experience over the past two decades, report authors conclude that an investment of $28.8 million could combine drinking water protection and flood control benefits for less than 10 percent of the cost of Maine’s current public water supply infrastructure.
Report authors recommend that individual projects be examined to determine the costs and benefits of each but conclude that “there is strong evidence both within Maine and elsewhere of the economic benefits of new strategies for water resource infrastructure” that “enable the use of natural infrastructure and diffused built infrastructure.
“The authors of this report paint a clear picture of the need and the opportunity we face in Maine today,” said Alex Mas, director of strategic initiatives for The Nature Conservancy in Maine. “We are blessed with exceptional water resources in this state, and timely, well-planned investments now can help ensure that they continue to provide benefits for communities across Maine and for future generations.”
Read the full report at: http://muskie.usm.maine.edu/Publications/AssessmentWaterResourcesMaine.pdf