Utilize Green Infrastructure in Great Lakes Areas of Concern

Part of the reason why remediation of a legacy of industrial pollution identified as Areas of Concern (AOCs) in the St. Clair River-Detroit River corridor is taking decades to achieve is the over-reliance on concrete and steel projects where green infrastructure would be more effective.

For example, as a means of stormwater control, public and private interests in New York City (including one auto company, Toyota) determined to plant a million trees in 10 years. They achieved that goal in eight years.

In the metro Detroit area (home of three auto companies), large-scale tree planting has been forsaken out of preference for huge concrete and steel projects like the so-called retention-treatment basins (RTBs). Nevertheless, downstream pollution, including sedimentation and turbidity, continues to be problematic.

Kuhn RTB - Oakland County, Michigan

One such, the massive Kuhn RTB (formerly known as Twelve Towns) in Oakland County, recently expanded, continues to divert partially screened and treated, sediment-laden surges down the Red Run Drain to the Clinton River and on to Lake St. Clair when overwhelmed by heavy rainstorms, instead of pumping the effluent to the Detroit Wastewater Treatment Plant as usual.

Better water quality in Great Lakes AOCs can be hastened by greater reliance on green infrastructure.

Stormwater Runoff Fees Omitted on 20,000 Detroit Properties

Over 20,000 parcels that contribute stormwater runoff but aren’t being charged will be added to DWSD’s billing system this October.

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Every year, billions of gallons of contaminated stormwater runoff and snowmelt pour off roofs, sidewalks, parking lots and other impervious surfaces into Detroit’s combined sewer system, then perhaps to a retention-treatment basin (RTB) and eventually to the wastewater treatment plant. The Detroit Water and Sewerage Department (DWSD), Detroit’s retail water agency for the Great Lakes Water Authority (GLWA), says this runoff costs more than $125 million annually.

Federal and state regulators required DWSD to spend more than $1 billion in combined sewer overflow storage facilities (RTBs) to reduce polluted overflows into natural waterways like the Detroit River. The drainage charge to property owners offsets this investment and the drainage treatment costs.

Most DWSD customers have been paying for drainage as part of their water and sewer bills. The City Assessor’s Office and DWSD are working to ensure that all parcels are billed for their share of drainage costs.

DWSD intends to begin a green infrastructure credit program in October. Customers who reduce runoff can earn credits to be applied to their bill. Fair, accurate billing and green infrastructure practices will benefit the city and its residents.

DWSD provides a  Parcel Viewer  on which to search for parcel information by address. Impervious surface area is used to calculate drainage charges. DWSD says it has data from the City Assessor's Office and flyover images to determine impervious surfaces. Property owners who disagree with the data can complete a drainage survey form.

Over 20,000 parcels that contribute stormwater runoff but aren’t being charged will be added to DWSD’s billing system this October. Customers who need to update parcel information or ask questions should contact DWSD.  A Customer Steering Committee meeting has been scheduled for July 14, 2016.

http://www.detroitmi.gov/drainage

Tear-up Abandoned Parking Lots

Less Costly Shortcut to Urban Stormwater Control 

Commercial property owners like to lay down as much concrete as they can, beyond what might be deemed necessary for parking and sidewalks, because in the long run it saves them the cost of labor, equipment and materials to cut grass and control weeds.  Some like asphalt even more because it’s cheaper than concrete, at least in the short run.

The drawback is that stormwater runs right off of concrete and asphalt (and roofs), straight into city sewers. In cities that have two sewer systems, one for household, commercial and industrial wastewater and a separate system for stormwater runoff, the consequences of storm runoff are less severe. It’s easier, thus less costly, to treat and moderate rainwater runoff.

Many older, larger cities like Detroit, however, have combined sewer systems where wastewater and stormwater flow together, often overwhelming wastewater treatment plants.

To meet the demands of clean water laws, some cities with combined sewers (like Chicago or Atlanta, for example) have been required to build huge tunnels to temporarily hold combined sewer discharges during and after storms, thereby preventing combined sewer overflows (CSOs) from inundating treatment plants or being released untreated into natural water bodies.

Several years ago, there were plans to build such a tunnel in Detroit, but the city’s insolvency prevented implementation. Instead, a number of smaller facilities called retention treatment basins (RTBs) were chosen to control overflows. Whether or not RTBs, some still under construction, will be sufficient to manage overflows and prevent the pollution of lakes and streams remains to be seen.

www.laurensgardenservice.com

In the meantime, various types of green infrastructure or low impact development (LID) offer some relief from the polluted runoff problem. These would include rain barrels, ground-level and roof-top rain gardens, permeable pavers, detached downspouts and bioswales. Note the success of one such LID project, a retrofit in the Towar neighborhood near East Lansing, Michigan;  http://detroitwatersewerblog.blogspot.com/2014/11/stormwater-success-story.html

But I digress. The point is that an overabundance of concrete and asphalt, mostly in underused or abandoned parking lots, contribute significantly to urban stormwater runoff and combined sewer overflows.

In metropolitan areas like Detroit, where populations have declined, sprawling parking lots at commercial, industrial, municipal, sports venue and similar sites could be reduced in size, sometimes drastically.

Consider the acres of unused pavement at abandoned sites like Northland Mall or the Pontiac Silverdome. Funds to remove hard surfaces would be available if we got our priorities straight.

Simply returning such areas or large parts thereof to their natural surface, augmented with vegetation of some kind, would be a lot cheaper than installing more concrete and steel RTBs or sophisticated green infrastructure improvements farther downstream.

Satellite view of Northland Mall’s empty parking lots:

https://www.google.com/maps/@42.4509185,-83.2060912,1375m/data=!3m1!1e3

Stormwater Management: More Trees, Less Concrete

Chicago built a giant stormwater/wastewater retention tunnel as part of the city’s Tunnel and Reservoir Plan (TARP).  It’s similar to the tunnel system recommended years ago for Detroit (which Detroit couldn’t afford).

But following storms earlier this week, Chicago’s Deep Tunnel filled to capacity and overflowed, spilling polluted stormwater into Lake Michigan.  CBS in Chicago (WBBN) reported, “ ‘All the tunnels combined, it’s 2.3 billion gallons of capacity that we maxed out,’ MWRD supervising civil engineer Ed Staudacher said.”

The lesson over and over again is that big, downstream, end-of-the-pipe processes and facilities by themselves aren’t the solution to combined storm and wastewater overflows in large metropolitan areas.

Another lesson is that concrete and steel remedies such as the retention-treatment basins (RTBs) that are being expanded in Detroit’s system cost more but aren’t as effective as well planned, region wide green infrastructure.

In New York City, Philadelphia and Los Angeles, for example, forward thinking leaders designed and are completing projects to plant a million trees each.

Trees generate oxygen, remove pollution, store carbon, save energy, improve water quality and slow stormwater runoff.

If each of the 120 upstream communities in the Great Lakes Water Authority (GLWA) system rallied service clubs, chambers of commerce, church groups and Boy Scout and Girl Scout troops to plant with thoughtful placement 1,000 trees per community per year, we’d have a million new trees in eight or nine years.  It’s doable.

GLWA, Don't Ignore Subsewersheds

There’s an opportunity now with the creation of the Great Lakes Water Authority (GLWA) to re-examine how ratepayer money is spent region-wide.

A good example would be efforts to reduce combined (storm and wastewater) sewer overflows in the River Rouge watershed.

In the past, Detroit water authorities concentrated efforts to reduce such overflows by building retention/treatment basins.  They have been augmenting the basins with green infrastructure, so far mostly by planting a few trees or disconnecting a few downspouts, in lower Rouge areas not far from the mouth of the river.

But the problem also occurs much farther upstream in subsewersheds.  Think of the big, interceptor sewers leading to the Detroit wastewater treatment plant as artificial rivers.  The many, smaller municipal sewer systems that feed the interceptors are like the creeks and ditches that feed natural rivers.

Reducing runoff into streams and sewers during heavy rains should begin far out in the Rouge watershed in places like Rochester Hills, West Bloomfield and Southfield.

River Rouge Watershed

Planting shrubs and trees, creating water gardens and swales, installing cisterns, paving with water-permeable materials, disconnecting downspouts from drains and impeding construction site and agricultural soil erosion throughout the watershed will pay dividends downstream at retention basins, pumping stations and wastewater treatment plants, as well as in natural water bodies.  Lower costs in the system translate into lower sewer bills for everybody.

This would be a good time for a vigorous collaboration between the new Great Lakes Water Authority and the State of Michigan to expand watershed-wide stormwater controls like those described above.