Impervious. Part III. The Rules, The Actions

What Are the Rules?

Parking lot bioswale

Parking lot bioswale

Rivers and lakes suffer many insults from human activities, but the Clean Water Act sets limits on how much sediment and chemicals they can receive. The EPA classifies polluters into point and non-point sources. Point sources are fixed locations like homes, stores and factories, and non-point sources are those that move around: trucks, trains, planes and cars.

Cities with more than 50,000 inhabitants have to get a National Pollutant Discharge Elimination System Permit (NPDES) from the DEQ. Nearly all construction projects, such as wind energy installations, have to acquire temporary stormwater management permits. But at this point, at every population level, alternatives to simply directing surface runoff into existing storm drains are entirely voluntary, for municipalities, businesses, and individuals.

While municipalities in the Gorge are too small to require NPDES permits, most small cities do have stormwater systems and some requirements for private management of stormwater. The Dalles currently requires anyone developing a property with more than three homes to submit plans for handling stormwater, says Dave Anderson, public works director for the city.

Typical stormwater collector

Typical stormwater collector

Developers usually do that, Anderson says, by “either connecting to the city stormwater collection system or developing an onsite stormwater detention system

[that] would have to accommodate a 25-year storm event.” A 25-year storm event for The Dalles? 2.6 inches of rain in 24 hours.

The City of Hood River is at “the beginning stages” of developing a more detailed impervious surfaces policy, says public works director Mark Lago. “We won’t be reinventing the wheel,” Lago says, and the city will likely look at Bend’s low impact development plan for guidance, which includes swales, rain gardens, and filtration systems.

The situation is similar on the Washington side. The Washington Department of Ecology, which manages stormwater mitigation for the state, doesn’t regulate any of the communities along the river between Washougal and the Tri-Cities because they’re too small, says Sandy Howard, a communications officer with the department. However, she adds,” the state encourages individuals and businesses to do what they can to improve water management on their property.” To this end the state has established the Washington Stormwater Center. The State of Oregon similarly encourages voluntary actions. “We are actively trying to promote low-impact development,” says Mason.

Copying the Metropolis

Big cities’ management processes aren’t always easy to adapt to small communities, but the City of Portland has taken a set of highly effective measures that could be adopted as-is. According to a Natural Resources Defense pull-quote-56000Council report, more than half of Portland’s area is impervious – far above the threshold for damaging an ecosystem – with roofs accounting for 40 percent and streets responsible for 25 percent of the barrier. The City requires all new city-owned buildings to have roofs that are at least 70 percent “ecoroof” and has published an ecoroof handbook along with a do-it-yourself guide for homeowners.

It has also disconnected some 56,000 downspouts on city property to allow upwards of 1.2 billion gallons of stormwater to soak into soil. Vegetated curb extensions along sidewalks have reduced peak stormwater flow during a 25-year storm by 88 percent and lowered the total runoff to the storm/sewer system by almost the same amount.

Individual Action

What are your options if you want to do the right thing and reverse or prevent your contribution to imperviousness in your location? You have quite a few choices.

After: driveway size cut down, pavers replaced concrete.

After: driveway size cut down, pavers replaced concrete.

Before: long double wide concrete driveway.

Before: long double wide concrete driveway.







  • Perhaps the easiest thing to do is disconnect your downspouts that send roof runoff into the storm drains and consider capturing that water for re-use.
  • Next time you need a new roof, you might install a green roof.
  • Re-landscaping your yard with native plants and abandoning the idea of a putting-green-perfect lawn will help reduce chemical runoff.
  • You can also convert part of your yard into a swale, rain garden or even a detention/retention pond.
  • If you have more paved surface than you need, consider taking up as much as possible of the unnecessary asphalt or concrete. There is a group in Portland called depave that provides resources, instructions, and other information for removing pavement and impervious surfaces in general, restoring soil and building permeable spaces like parking lots.

Rehabilitating stressed land and water resources seems like a slow process in which the actions of individuals may seem too insignificant to matter. But this is an illusion, and many of the steps to reducing impervious land cover are inexpensive and relatively easy. We just have to alter our definition of responsible property ownership to include care for the soil and water our structures and practices affect. This can also improve our own quality of life in a relatively short time. And you can still be a neatnik – but one who protects a necessary and treasured ecosystem.


Read Part I and Part II of our Impervious Series. 

By | 2016-12-13T01:59:33+00:00 March 11th, 2015|Categories: Energy and the Environment, News, River Environments, Water Environments|0 Comments

About the Author:

Valerie Brown, lives near Portland, Oregon. She specializes in science and environment writing, particularly environmental health and climate change, including the health effects of chemical and radiation exposures, carbon sequestration, and climate change’s effects on forests and oceans.

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