[Durham INC] INC-list Digest, Vol 91, Issue 2

Mon Jul 2 12:58:50 EDT 2012

There is a "Rock the Park" concert this Saturday at Old Farm Road Park. It is from 6pm - 8pm and is free to the public. Please come out and support.

Rukea N. Womack, MBA
Recreation Manager: Special Events & Latino Outreach Unit
City of Durham Parks and Recreation Department
400 Cleveland Street
Durham, NC 27701
P: (919) 560-4355 ext. 27228
F: (919) 560-4021 
Rukea.Womack at durhamnc.gov

www.DPRplaymore.org

"Durham Parks and Recreation provides opportunities for our community to PLAY MORE!"

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Today's Topics:

   1.  DDFC Stormwater Site (Will Wilson)
   2.  Durham Encourages Water Efficiency During Smart	Irrigation
      Month (Blalock, Amy)

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Message: 1
Date: Mon, 02 Jul 2012 09:00:36 -0400
From: Will Wilson <willwilsn at gmail.com>
To: inc listserv <inc-list at durhaminc.org>
Subject: [Durham INC] DDFC Stormwater Site
Message-ID: <4FF19B74.2050903 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

All,

I wanted to comment on and provide a bit of background concerning the INC and DOST presentations on the Duke Diet and Fitness Center (DDFC) stormwater facility, primarily concerning water volume and water quality. Sorry it's long, but I wanted to include background information, too. I teach a stormwater course at Duke, presently writing a book on stormwater, and have a pretty good grasp of the science, however, the mish-mash of federal, state, and local regulations are more confusing and less rational than science. So, as the recent sea-level-rise fiasco shows, there's science, and then there's regulations. I don't have a strong expertise in regulations.

The Basic Problem:
--- ----- --------
Urban areas have lots of impervious surfaces, which are covered areas where rain doesn't directly fall on the ground: parking lots, roads, houses, sheds, parked cars, etc. When it's not raining, pollutants settle on these surfaces, and these pollutants include nutrients, oils, heavy metals, salt, pesticides and herbicides, and more. Much more pollution settles out in urban areas than rural ones, and most biologically available nitrogen (in our area) comes from burning fossil fuels -- cars, trucks, coal, but emissions controls help reduce that load. Regions with heavy agricultural uses are different than ours. Even tire and brake wear add significant amounts of various other pollutants. 
Storms wash these pollutants off of the impervious surfaces, and the highest pollution concentrations in the stormwater are found in the "first flush", or the initial stormwater flow off of a site.

In addition to pollutants, stormwater rushing off of impervious surfaces leads to high peak flows downstream, like the sudden rush of water from a toilet, and leads to a phenomenon called the "urban stream syndrome". 
High, flashy flows deeply erode streams, not only carrying the eroded sediments downstream, but the resulting stream profile acts almost like a drainage ditch during the dry periods. These "ditches" drain groundwater near the stream, which dries out the stream-side vegetation (the riparian zone), and reduces the nutrient processing abilities of these urban streams. Leaky sewer pipes previously submerged below the water table drew water into the pipes, but a lowered water table can instead let its contents leak into the dry soils.

To deal with pollutants and flashy flows, "stormwater control measures (SCMs)" try to intercept and contain the first one inch of rainfall to promote settling, evaporation, photodegradation, and bioretention of the contained pollutants. Slowly releasing this water also reduces peak flows and helps preserve stream ecosystems that process nutrients, as well as emptying out the volume of the SCM in preparation for the next storm. Of course, these SCMs have to be built carefully to not wash away when 6 inch storms come along.

As gardeners know, plants desperately want more nutrients, and algae in lakes are no different. We learned long ago that nitrogen in lakes make algae flourish, but algae-eating animals can't keep up, and when all that algae dies, bacteria break down all that "algae compost" and use up all of the oxygen in the water. That lack of oxygen makes fish die, the water stinky, and leads to all sorts of other problems. We've added nutrient regulations to deal with the problem of nutrients.

Solutions:
----------

The Falls Lake nutrient reductions are part of those regulations, and the exact numbers for the various implementation stages aren't so important, but the concept is clear: we must reduce the nutrients flowing into the lake. We are "graded" on the nutrients in the streamwater right where it flows into the lake, so as far as nutrients go at that spot, a reduction of 100 pounds anywhere upstream is a reduction of 100 pounds. We should all support our stormwater services department in finding the places upstream where the most reductions can be done for the least amount of taxpayer money. Downtown is likely a disproportionately high source of the nutrients, but it's also an extremely expensive place to reduce them, in part because land prices are high and undeveloped land is limited. So, just from the perspective of nutrients, there is a reasonable argument that we should make the reductions where they're the cheapest.

Stormwater volume is a different matter. In undeveloped watersheds, rain falls across the entire watershed, evaporates or helps plants and trees grow, or soaks into the ground. That's a process that naturally holds back water throughout the watershed until it seeps from groundwater to streamwater. In urban areas, all that water quickly flushes downstream because impervious surfaces prevent it from soaking into the ground. We need to hold that stormwater back or sacrifice all of the natural, downstream nutrient processing capabilities. We could hold back that volume with one big facility way downstream like the DDFC site, or lots of smaller facilities farther upstream using a variety of control measures.

Let's think about the Duke Diet and Fitness proposal. Above that spot is about 500 acres of watershed with a high fraction of imperviousness, and, if you have a one inch rain over that area, you could think of the volume as a temporary 500 acre lake that's just one inch deep, or a one acre lake that's 500 inches deep, or anything in between. The DDFC site is 9 acres, meaning it would need to be about 56 inches deep (about 5
feet) to hold that volume, assuming no wetlands media in the pond. Using less land for the pond at that site means a deeper pond, or not holding all of the water volume at that location.

There are many ways to deal with this volume, including "caverns" built under parking lots, which provide irrigation water for green roofs and urban trees that help cool our city that reduce our energy demands and improve air quality. These large cisterns also just collect stormwater that can slowly be released like a detention pond, without any water use. Here is a link to one such parking lot approach: 
http://stormtrap.com/. Do we have a few acres of parking lot downtown that could serve this purpose? Let me also provide a link to a free magazine, imaginatively called "Stormwater": http://www.stormh2o.com/. 
Many more approaches to stormwater treatment are discussed here: 
http://www.epa.gov/oaintrnt/stormwater/best_practices.htm.

The DDFC Presentation:
--- ---- -------------

During the presentations I've heard, it has been stated that using less than the full site simply won't work. I have seen much smaller constructed wetlands, and it is not at all clear why a 3-, 5-, or 7-acre pond simply can't work at the DDFC site. Small constructed wetlands exist and function properly, so it can't be a matter of science. I don't understand that assertion and direct questions on that issued are deflected.

The DDFC stormwater presentation describes and promotes a policy choice, and lacks a full explanation of the range of policy choices available to citizens. Various folks at INC described the broader issue nicely: In the urban area, we need to think holistically about the solution to the stormwater problem, and break down any silos that prevent considering other benefits like water parks, education, urban cooling, and urban trees. There will be a lot of money devoted to the issue no matter the choices, and if we can solve problems beyond stormwater at the same time from the same dollars, or even if alternative approaches might well be more expensive, citizens might prefer these additional environmental amenities and services for a little additional cost. This situation is a wonderful opportunity to discuss downtown green infrastructure desires and needs, and the DDFC presentation sidesteps that opportunity.

Durhamites may well choose the cheapest option of using the DDFC site to handle all the water volume and incentivize optional green roofs downtown. However, we should also consider the option of a partial solution at the DDFC site and requiring subsidized green roofs downtown, along with a more comprehensive set of green infrastructure. That is a policy choice for citizens to make, and we need complete information from the stormwater department. The stormwater department faces a challenging problems and continuously changing regulations, but I would encourage them to present the full array of policy choices available to the city.

Will Wilson

--
http://www.biology.duke.edu/wilson/
New Book: http://www.constructedclimates.org/

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Message: 2
Date: Mon, 2 Jul 2012 11:04:41 -0400
From: "Blalock, Amy" <Amy.Blalock at durhamnc.gov>
To: "Blalock, Amy" <Amy.Blalock at durhamnc.gov>
Subject: [Durham INC] Durham Encourages Water Efficiency During Smart
	Irrigation Month
Message-ID:
	<5DF632A1980EE94A895393F2DAC54B590791ACC6 at EXCHANGE2K3.durham.local>
Content-Type: text/plain; charset="us-ascii"

CITY OF DURHAM

Office of Public Affairs

101 City Hall Plaza

Durham, NC 27701

News Release

News Media Contact:

Amy Blalock

Sr. Public Affairs Specialist

(919) 560-4123 x 11253

(919) 475-7735 (cell)

Amy.Blalock at DurhamNC.gov 

Like: http://Facebook.com/CityofDurhamNC 

Follow: http://Twitter.com/CityofDurhamNC    

For Immediate Release: July 2, 2012

Durham Encourages Water Efficiency During Smart Irrigation Month

Odd-Even Watering Schedule Still in Effect to Help Manage City's Water
Supply

DURHAM, N.C. - Summer has definitely arrived and with it record-breaking
temperatures, resulting in wilting flowers and shrubbery. However, now
is the time to use water efficiently and not overwater, particularly
since the City of Durham is officially recognizing July as Smart
Irrigation Month. 

The Irrigation Association, a non-profit industry organization dedicated
to promoting efficient irrigation, has named July as Smart Irrigation
Month since July is traditionally the month of a peak water demand. This
is partially due to increased watering for lawns, gardens, and
landscapes and the association points out that many property owners
overwater lawns and landscapes by up to 30 percent. 

According to the City's Water Management Department, by selecting
appropriate vegetation and planting carefully, watering wisely, and
maintaining and upgrading automated irrigation systems, property owners
can save money, save water, and see better results in their lawns and
gardens.

The City's Water Conservation Program provides valuable information and
assistance to help Durham property owners save money and help preserve
Durham's most valuable resource - water. For more details, download the
"Water Wise Watering and Landscaping Guide" at 
http://durhamnc.gov/ich/op/dwm/Documents/Conservation%20PDF'S/waterwiseg
uide.pdf. 

As water demand increases, the City's Water Management Department is
also reminding residents to follow the Odd-Even Watering Schedule, since
irrigation during summer months can increase demand on the treatment
plants between 20 and 40 percent. For more information on this schedule,
visit 
http://durhamnc.gov/ich/op/dwm/Pages/Odd-Even-Watering-Irrigation-Schedu
le.aspx. 

For more general information on water conservation and efficiency, visit
http://www.DurhamSavesWater.org or "like" 
http://www.Facebook.com/DurhamSavesWater. 

About the City's Water Management Department
The Water Management Department is responsible for the operation and
maintenance of Durham's water supply, water treatment and water
reclamation (wastewater treatment) facilities, the collection and
distribution systems (including meter reading), and customer billing
services. The department has a wide variety of support divisions and
programs to maintain the existing infrastructure that provide these
integral services and strive to be a responsible steward of the City's
physical assets. For more information, visit  
http://DurhamNC.gov/ich/op/dwm <http://durhamnc.gov/ich/op/dwm> .

About the Irrigation Association

The Irrigation Association, a non-profit industry organization dedicated
to promoting efficient irrigation, named July as Smart Irrigation Month
to increase public awareness about simple practices and innovative
technologies homeowners, businesses, and property managers can use to
save money on utility bills; minimize or defer investments in
infrastructure to store and carry water, typically paid for by property
taxes or municipal bonds; and protect their community's water supply for
generations to come. For more information, visit 
http://www.Irrigation.org.

###

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