The Rain Gauge

Making Every Drop Count - Texas Style

2011-08-26T08:34:00.000-07:00

Great Article at NYTimes.com "Making Every Drop Count"

http://www.nytimes.com/2011/08/25/garden/prairie-grass-landscapes-in-austin-tex.html?pagewanted=1&hpw

"WITH 70 days of 100-plus temperatures so far and no rain in sight, Austin is in the grip of its worst one-year drought on record. And gardeners are quickly finding out which plants can survive brutal heat and drought.

Native trees like cedar elms and hackberries are dropping their leaves. Ash junipers in the Hill Country are dying. Shallow-rooted azaleas and crape myrtles are toast, and most lawns are brown, except for those watered by private wells.

Animals are suffering, too. Coyotes and rabbits are showing up in city gardens in search of water and food. Hummingbirds can’t find nectar because many plants aren’t flowering.

The first week of August, when daily temperatures climbed to 107 or so, a bison escaped from a ranch in Manchaca, on the southwest side of the city, and wandered into the Lady Bird Johnson Wildflower Center seven miles away, where it spent several days grazing in the savanna grasslands.

Gardeners are embracing those prairie grasses with equal enthusiasm because of their heat and drought tolerance. These natives can be found in many of the city’s lawns, ornamental gardens and even green roofs. Remarkably, these deep-rooted plants can adjust to shallow soils, helping to cool houses and absorb rain — when there is some.

“If we get a rain, these grasses will all turn green,” said Lars Stanley, 59, an architect and metal artist, standing on a roof planted with natives that covers the studio he built in East Austin with his wife, Lauren Woodward Stanley, 45, an architect. “It reduces our cooling level immensely.”

The grasses (blue grama, curly mesquite, little bluestem and sideoats grama) go dormant in a drought, a survival strategy that keeps their roots alive. But the prickly pear and Texas sedum the Stanleys planted, succulents that store water in their fleshy pads, looked remarkably fine. " more at link above....

Norman's Water Quality Protection Zone

2011-08-01T10:43:00.000-07:00

The city of Norman has released the Storm Water Master Plan which they have been working on since 2005 when they hired PBS&G to do research on how to improve water quality problems to prevent water erosion. The Storm Water Master Plan recommended that the City enact regulations that would provide buffers around the streams and Lake Thunderbird Watersheds as part of the overall effort to improve water quality.Most of Norman’s drinking water is collected from Thunderbird Lake. The contamination in this lake has been linked with the city’s water sheds as well as the general runoff from the Lake’s surrounding area. Therefore, the city has created a new ordinance which will reduce contamination from construction site around these areas.

As of June 28th 2011, the city amended and passed a new ordinance to protect land around the lake as well as officially adopted the Storm Water Master Plan. The ordinance that did pass has been called a “watered down” version of the original and it went into effect of July 28th. The second ordinance dealt with the Water Quality Protection Zone (WQPZ) and would have involved a zoning overlay of Norman. The zoning ordinance did not pass and according to the city of Norman they “have no immediate plan” to discuss it in the future.

Only half of Lake Thunderbird is in Norman’s jurisdiction. With the amount of protests to the new ordinance, it seems that the people of Norman are forgetting the final goal and focusing on the new restrictions and cost instead of the major benefits. This focus on water quality is a new idea but will hopefully create change for the better in other cities as well. “The Norman City Council’s move to protect water quality in Lake Thunderbird will put pressure on Oklahoma City and Moore to enact similar policies. Any new law or resolution draws attention to the unsafe levels of toxins in our drinking water. So the Water Quality Protection Zone (WQPZ) enacted by the Norman City Council is not just a move that reduces the pollution Norman is responsible for — it also is a necessary first step to improving water quality to tolerable levels.” – The OU Daily

The WQPZ is typically a strip of land on a larger parcel that abuts a stream. The new regulations only affect property that have plans to be developed in the future, and are located in the Lake Thunderbird watershed, and contain a stream or designated floodplain. The plan is meant mainly to protect Lake Thunderbird. It does not give the government permission to take away land as rumored, but the new ordinance does force those wanting to develop areas around the lake within the previously described land to ask for permission.

THINGS YOU SHOULD KNOW ABOUT THE ISSUE:

Thunderbird Lake provides 75% of Norman’s drinking water as well as drinking water for Del City and Midwest City.

The Lake has been classified as “impaired” by the Oklahoma Department of Environmental Quality. It has been reported that levels of chlorophyll-A are seven times greater than regulation standards. It has further been reported that the elevated amounts of nitrogen, phosphorus, dissolved solids and sediment put the Lake at risk of developing algal toxins that threaten public health and recreational uses.

The lake is Eutrophic.
---This means, the lake has a high concentration of nutrients, particularly Nitrogen and Phosphorus, which promote excessive growth of algae. High levels of algae also cause taste and odor problems for our drinking water. To add to the problem, when the algae dies and decomposes, it depletes oxygen in the water and can cause fish kills.
A way you can help is to make sure nothing goes down a storm drain other than rain.
---Storm Drains are the drains commonly seen on the side of street everywhere from neighborhoods to busy streets.

A common misconception about the recently passed ordinance is that the government can take your land without compensation. This is completely false.
---Some see the restriction of developing land as a violation of the right to property but in no way is the City of Norman confiscating land. It is more similar to a utility easement, which limits the types of development that can occur on a piece of land.
The City of Norman has a permit from the state which requires the state to reduce pollution in storm water runoff. In addition to requirements that they regulate runoff from construction sites, reduce pollution from City operations and remove illegal connections to the storm sewer. They also must have a program to inform the public (you) about things they can do to reduce storm water pollution.

If you would like any additional information here is the City of Norman's web page for the issue:

http://www.ci.norman.ok.us/content/storm-water-master-plan

New Contruction Turbidity Standards

2011-07-28T14:59:00.000-07:00

Land and Water Magazine: Reducing Turbidity, ELG’s, and Compost-Based BMPs

Summary

The final rule for the US EPA Effluent Limitation Guideline for the Construction and Development Industry (40 CFR Part 450 of the Federal Register) went into effect in February 2010. The new rule creates storm water quality performance standards for soil disturbance on construction sites 10 acres or greater. The land owner will be required to monitor and report the daily average nephelometric turbidity (NTU) from waters discharged from the construction site. The turbidity standard (numerical limit) to trigger a violation was originally 280 NTUs.

Under the current rule, the US EPA will begin enforcement on construction sites with a total active soil disturbance of 20 acres of 20 acres or greater as of August 2011. Sites that disturb 10 acres or greater will undergo active enforcement starting February 2014. For large developments this includes the sum total area of disturbance at any given time, including small sections under the acre limit.

Effluent Limitation Guideline (ELG) states the permitted party must report the daily average turbidity from all site storm water discharge areas. A violation will only occur if the daily average exceeds the NTU threshold, whereas, one reading in breach of the NTU limit does not constitute a violation. Also, if the 2yr 24hr storm event is surpassed for the local area where the construction site is located, the turbidity standard will not be enforced.

Storm water sampling frequency, number of daily samples required, sampling methodology, sampling equipment, method of measurement, and reporting method is up to the local permitting authority. Although, the US EPA will likely release a guidance document which will likely steer the permitting authorities.

The Final Rule does not dictate what type of best management practices can be used as the US EPA does not want to limit strategies that may help permitted parties comply with the new rule. They estimate that full enforcement and compliance with the new rule will encompass 73% of construction site soil disturbance nationally and should reduce annual sediment discharges from construction sites by 77%

For those with sites of 20 acres or greater, this rule will be effecting you very soon. The new standards have been described as strict and depending on the site type may be difficult to comply with. Remember that the owner is in-charge of reporting the daily average NTU, and should also be considering ways to reduce the turbidity level to keep it under limitations. The link below gives an article which includes suggestions for reducing turbidity levels: http://viewer.zmags.com/publication/f15cb27c#/f15cb27c/24

EPA Launches Green Infrastructure Strategy

2011-07-08T08:21:00.000-07:00

WASHINGTON – The U.S. Environmental Protection Agency (EPA) is launching a new strategy to promote the use of green infrastructure by cities and towns to reduce stormwater runoff that pollutes our nation’s streams, creeks, rivers, lakes and coastal waters. Green infrastructure decreases pollution to local waterways by treating rain where it falls and keeping polluted stormwater from entering sewer systems. In addition to protecting Americans’ health by decreasing water pollution, green infrastructure provides many community benefits including increased economic activity and neighborhood revitalization, job creation, energy savings and increased recreational and green space.

“Through this agenda, we’ll help cities and towns across the nation clean up their waters and strengthen their communities by supporting and expanding green infrastructure,” said Deputy Administrator Bob Perciasepe, who announced the agenda at a Green Street, Green Jobs conference focused on fostering green infrastructure in the Washington, DC metropolitan area. “Green infrastructure changes improve the health of our waters while creating local jobs, saving communities money and making them healthier and more prosperous places to raise a family and start a business.”

Stormwater is one of the most widespread challenges to water quality in the nation. Large volumes of polluted stormwater degrade our nation’s rivers, lakes and aquatic habitats and contribute to downstream flooding. Green infrastructure captures and filters pollutants by passing stormwater through soils and retaining it on site. Effective green infrastructure tools and techniques include green roofs, permeable materials, alternative designs for streets and buildings, trees, rain gardens and rain harvesting systems.

As part of the strategy, EPA will work with partners including local governments, watershed groups, tribes and others in 10 cities that have utilized green infrastructure and have plans for additional projects. EPA will encourage and support expanded use of green infrastructure in these cities and highlight them as models for other municipalities around the country. The 10 cities are: Austin, Texas; Boston, Mass.; Cleveland, Ohio; Denver, Colo.; Jacksonville, Fla.; Kansas City, Mo.; Los Angeles, Calif.; Puyallup, Wash.; Syracuse, N.Y.; and Washington, DC and neighboring Anacostia Watershed communities.

Energy savings is one of the greatest benefits of green infrastructure. On and around buildings, green infrastructure can reduce heating and cooling costs. For example, green roofs reduce a building’s energy costs by 10 to 15 percent, and an additional 10 percent of urban tree canopy can provide 5 to 10 percent energy savings from shading and windblocking. Green infrastructure also conserves energy by reducing the amount of stormwater entering combined collection and treatment systems, which reduces the amount of wastewater processed at treatment plants.

EPA will continue to work with other federal agencies, state and local governments, tribes, municipalities, and the private sector to identify opportunities for using green infrastructure and provide assistance to communities implementing green approaches to control stormwater. EPA will also provide additional tools to help states and communities leverage green infrastructure opportunities within other innovative environmental projects.

For more information on EPA’s green infrastructure agenda: http://epa.gov/greeninfrastructure

Green Roof for Tulsa City-County Central Library!

2011-07-01T12:31:00.000-07:00

The Tulsa City-County Central Library, constructed in 1965, formerly included two reflecting pools flanking the main library entrance. The reflecting pools were built over an underground parking structure - and over time -the pools began to leak, damaging cars and creating a hazard. And so, the pools were emptied and sat abandoned for years. They became an eyesore, and a maintenance issue.

The library evaluate using the former pools as landscaping, but faced challenges due to soil loads on the parking structure roof. But, observing rooftop gardens, they began to see other opportunities for reuse.

After consultation with structural engineers, the library confirmed that a roof system would be feasible. The project was fully funded by the American Recovery and Reinvestment Act "Green Project Reserve" adminstered by the Oklahoma Water Resources Board.

The first step was to remove the old terrazzo and install a new waterproof membrane to correct leakage problems. The next step was to add insulation and a root-stop barrier. The bottom white later is styrofoam insulation, which was also helped to raise the bed.

Next, a moisture retention layer was added. This was critical due to the long, hot, dry summer in Tulsa as well as the garden's location on a southern exposure. Roof top gardens often also have moisture loss from constant winds. Rather than using soil, LiteTop(r) growing media was utilized to help minimize weight.

Plants were chosen to minimize the need for irrigation and maintenance. A drip irrigation system was installed to assure plant survival while minimizing water consumption. The landscaping design was developed specifically to deter misuse or vandalism of the beds. The final installation is an attractive as well as educational addition to the library. Along with overall beautification, the library has seen a decrease in the amount of abuse and litter in the surrounding plaza.

2011-06-20T09:05:00.000-07:00

Last year the Tulsa City-County Library System received two grants to install green stormwater management systems. We have recieved a presentation from the Library showing the sites, design elements, and final products for both installations and will be posting them here. Go by and check these out yourself!

The first is at the Judy Z. Kishner Library, located in a Sperry, OK. The library was completed in 2008 and lies in a two acre lot adjacent to the Osage Trail. Nearly the entire town, along with areas to the north, is prone to flooding. The contours and elevations of the library property did not allow positive drainage off the site and were a mosquito haven.

Since draining the water was not an option for this property, the idea of a rain garden took shape.To fund this project, the Library applied for a grant from the Amercina Recovery and Reinvestment ‘Project Green Reserve’ administred by the Oklahoma Water Resources Board. Due to the innovative nature of this problem resolution, the project was fully funded with the Green Reserve Grant Funds.

During construction, the existing surface depression was excavated further and the soil amended. New vegetation, selected to enjoy the wet conditions, was planted. The finished result is an amenity for the library and the nearby trail as well as a stormwater management feature.

TulsaPartners Raingarden - Plant Selection

2011-02-03T13:14:00.000-08:00

Shown to the left are plant descriptions for several of the varieties we used in the TulsaPartners' raingarden. You'll notice most of the descriptions feature a butterfly sticker, which indicates that they attach pollinators, like butterflies. You may also notice that we generally selected 1 gallon (1#) container sizes, which are lower priced, but generally fill out well within a season or two.

Color. Because the building is a light yellow and there are already lavender flowing plants present (a lilac bush sits just behind the raingarden), we kept with that theme and selected plants that would have lavender or yellow flowers. Because the building is surrounded by an evergreen hedge, which also forms the garden's backdrop, we didn't invest in additional evergreen material.

Moisture Tolerance. In general, plants in the deepest section of the garden will have the greatest depth and duration of inundation, so these plants should be water-loving or wetland-type plants. For this garden, we looked around the building for plants that were already present and found an overgrown clump of purple irises, which do well in wet soil. In addition, they are vertical plant and wouldn't get lost due to height. Some of these were transplanted into the deepest part of the garden. In the middle zone, we planted another popular lavender flowing plant, garden phlox, along with a yellow flowering plant, Helianthus. Both tolerate moderate levels of inundation but also do well with direct sun and periods of drought. In the back, which is the driest part of the garden, we planted Russian sage and Little Joe Pye Weed. The "Little" is important because a normal Joe Pye Weed would take up almost all of a garden this size!

Russian sage has a nice silvery green color and texture that indicates it takes drought well. The lawn and plantings at TulsaPartners are not irrigated, so these plants need to be able to take a beating.

With Spring just around the corner, I'm looking forward to seeing how these plants have handled the long dry fall that followed their installation. Stay tuned for more photos!

Raingarden Irony

2011-02-03T11:53:00.000-08:00

The wonderful irony of the raingarden featured below, which we installed at the TulsaPartners, Inc. office in September 2010, is that it HAS NOT RAINED significantly since then. And we always get the question - "Do I need to water my raingarden?" The short answer is "Yes", especially in the first year or if it hasn't rained for a while. Raingardens should be designed to feature water-loving plants as well as plants that can handle both dry heat and periodic flooding. And this means that they do need to be watered, especially for the first growing season. Come Spring, we'll see what of this garden survives. My bet is on the Russian sage.

Building a Raingarden for Tulsa Partners

2010-09-14T07:24:00.000-07:00

As part of the kickoff of Tulsa Partner's Green Building Resource Library on September 24th, we will be installing a raingarden at the TPi office! There's a good bit of prep work that goes into building a raingarden, so I thought I would use the blog as repository of everything we can't get into the short on-site workshop we'll conduct that evening.

I went by today and took few photos of the office. The downspouts are already disconnected, so that is one thing we won't have to do. There is one downspout on the southeast corner of the building that discharges to a sunny, grassy spot. Its visible from the street and building entrance, which is great from an educational perspective. Its also in a nice sunny spot, which gives us a good range of plants to work with. See the downspout on the right side of the roof overhang.

I then walked off the area of the roof handled by this downspout. Its about 20' across and 25' long, or 500 sf. I'll do a field check of infiltration later, but just as a starting point we could assume 6" of infiltration/24 hours, resulting in a 6" deep garden. For a garden that would handle the first 1" of runoff, that would require 500/6 = 83 sf of garden. The space available is 80sf, max. So, let's say we get more infiltration, say 8"/24hours. That would make our garden 500/8 = 62.5 sf. Probably more likely to fit the space, but we'll check the infiltration to be sure the soil can handle it.

What if we don't have the infiltration needed for this size roof? Just size the garden depth for the infiltration (depth = infiltration in 24 hours but 12" maximum). A smaller garden than your runoff volume requires just means you'll be capturing less than the first 1", and the first 0.5" is typically the most important, so that gives you a good range for the available space.

Here's another look at our site.

Ready for a Green Roof? Try This!

2010-08-17T09:38:00.000-07:00

Ok, this is a DIY project for LIDers who want to try out a green roof, but may not be ready or able to tackle something full-scale. How about a green doghouse, or shed? This is a no-power-tools-required project that can be done over a weekend, or with a few hours here and there.

Step 1: Cover the roof that came on the structure with roofing felt cut to size with a utility knife. Attach it using gavanized roofing nails.

Step 2: Creat two frames to hold potting soil mix (regular soil is too heavy) by attaching cedar or treated 1x4s to the front , sides and ridge of the roof using galvanized nails. Add a 1x4 board across the middle of each side, horizontally, to help reduce soil erosion when it rains.

Step 3: Fill in the frames created in Step 2 with a thin layer of gravel overlain by potting soil. Cut chicken wire with wire clippers to cover the frames, staple chiken wire to the wood to hold the soil in place. (At our house, the dog recently destroyed a bean bag chair, so we amended the soil with those tiny beads to improve its drainage and weight!)

Step 4: Plant succulents or low growing plants that are adapted to the climate in your area. Look around your garden - what already grows and spreads without being watered? Use it! Shake excess soil from the roots, snip a hole in the chicken wire, and carefully (the wire is sharp!) tuck the roots in. Finish by filling the spaces between plants with sheet moss. The plants will quickly cover the moss and hang over the edges.

Step 5: Water about twice a week intially, until plants are establisted. Feed during growing season with 20-20-20 water soluble fertiler to keep it looking its best.

Depending on how well the structure is supported, you could try this on a playhouse, shed, chicken coop or detached garage. Larger structures will likely need additional support. Have fun and get green with this great LID project.

This project was edited from Southern Living's June 2010 edition, by Joyce Butterworth.

What's the Difference?

2010-08-16T13:55:00.000-07:00

These photos are not intended to pick on Home Depot but are representative of most big box development. Question: What's the difference in these two photos? The top photo is typical of what we see most commonly in Oklahoma commercial development - big box, big parking lot, big runoff. But what of the second photo - same company but a very different approach. Is it geography? Is it rainfall? A unforeseeable landscaper strike? The answer is actually none of the above, but rather Policy. The second photo represents development in a community that asks more, and recieves what they ask for. And not that they ask, but they require, through codification, that their community be cared for in specific ways. I was watching "Cars" with my kids and found motivation from the local lawyer asking "Are we worth having this done right? Is our town worth it?" when the residents were satisfied with status quo.

I would like to ask our councilors, our mayor, our public works officials: Is our town worth it? Is our river worth it? Asking for funding for river development is somewhat futile if we won't also take enough pride in our community to say - do more than the minimum. The difference is not what you see, its what you don't see: the policies and codes that say our community is worth the effort.

What are the most common LID practices in Tulsa?

2010-08-03T20:48:00.001-07:00

I had someone ask me this question recently and it made me run around town to take some more pictures. LID that has been designed intentially to improve stormwater quality or affect stormwater quantity is not easy to find. What is more common are aesthetic landscaping features that accomplish this task. One example is canopy cover. Tulsa has long reaching goals for canopy cover and recovery/replacement of trees lost in 2007's ice storm. A great side effect is that canopy cover, when trees are in leaf, significantly reduces stormwater runoff. The effect is huge compared to areas of pavement. Some common examples are trees planted in medians, which only achieve the desired effect when they overhang roadways and sidewalks. Here are some local examples:But there are places that go above and beyond when placing trees. One of my favorites is the area surrounding One and Two Warren Place, at 61st and Yale. The roadway to the right is one example. They have included a mix of deciduous trees (median, right of photo) which affect stormwater runoff during parts of the year, and also evergreens, which achieve the same effect year round. And if you have the chance to visit, take a look behind One Warren Place (1st photo above) and see the surface parking. The plantings could make you forget you were in an urban setting, and are a far cry from the standard surface parking you would see downtown, or anywhere else for that matter.

Heifer International - Wetlands

2010-05-04T19:30:00.001-07:00

We're back to Heifer International in Little Rock - there was so much to write about! Besides rainwater use on-site, rainwater is also collected and treated through a variety of LID systems. One are the wetlands shown in the previous post. In practice, rainwater falls on the roof, which has been finished as something closer to a swimming pool than your typical roof.

Rainwater is channeled into downspouts, which have been designed as a functional architectural feature. The kids thought these would be great slides during the rain!

The downspouts become horizontal channels closer to the ground. Rainwater flows over the side of the channel, which function like a weir, into the stabilized forebay of a raingarden. You can see the channel as well as reeds in the raingarden to the right.

A surface drain at the end of the raingarden allows stormwater to flow into the wetlands at the site. The wetlands surround the main office building, giving it a castle and moat feeling. But most of all it's lovely, with ducks, turtles and fish enjoying this site, which was previously a contaminated industrial facility.

Below is a design schematic for the wetlands, similar to many, many we've seen in LID and stormwater guidance manuals. But not as often do we have the opportunity to see them in place, in practice. If you happen to be in Little Rock, look behind the Clinton Library for this green gem!

Lessons Learned - Heifer International

2010-05-03T21:43:00.000-07:00

Greetings! Now that the grass is green and the rain has begun to fall, I'm feeling like a blogger again. Whew!

In March we traveled to Arkansas and visited Heifer International in Little Rock, Arkansas. Their 24-acre urban headquarters is a far cry from the village agriculture that characterizes Heifer projects. However, the sensitivity to environmental issues is a theme carried through in site planning and development. There are a number of features we'll highlight in the next few weeks. The first is the facility's use of water recycling and rainwater collection.

The building boasts an impressive recycled water and rainwtaer collection cistern that holds 25,000 gallons. This water is used in the building's heating and cooling systems as well as for other non-potable uses, such as toilets and irrigation. The tower is built in to the north wall of the building, adjacent to an elevator shaft, so that its profile doesn't seem out of place with the rest of the structure.

Another feature is the treatment wetland you see in the foreground of the above photo. But we'll talk more about that next time.

Turbidity Limit on Construction Phase SW Challenged

2009-12-10T07:35:00.000-08:00

from Inside EPA Water Policy Report - 12/7/2009

Key Republican lawmakers are slamming EPA’s just-signed regulation governing stormwater discharges from construction sites, saying it is far too costly for the environmental benefits derived. EPA’s rule is in the top five least cost-effective regulations, across all federal agencies, since the White House Office of Management & Budget (OMB) began tracking such figures in 1992, according to industry’s review of OMB’s records.

“I am extremely concerned about the impact this rule will have on economic recovery in the U.S.,” Sen. James Inhofe (R-OK), ranking member of the Senate environment committee, said in a statement to Inside EPA.

At issue is EPA’s just-signed, court-ordered rule governing stormwater runoff from construction sites. EPA included in the rule a numeric limit for turbidity prompting industry criticism because it will cost almost $1 billion per year to fully implement. (Note: This is a significant change from previous regulations, which said that certain practices must be followed, but did not specify outcomes.)

The construction and development sector effluent limitations guideline phases in a numeric limit of 280 nephelometric turbidity units (NTUs), a unit of turbidity, and requires “passive” filtering technologies to meet the standard. (What does 280 NTU look like? See the image below:)

Inhofe singles out in particular the controversial numeric turbidity limit in the regulation for criticism. “[T]he rule sets an arbitrary ‘turbidity’ benchmark that will be extremely cost burdensome for builders to achieve, especially with the current limited technology. It also provides yet another tool for environmentalists to delay or stop important development and transportation projects through frivolous litigation,” Inhofe said.

Although EPA is only requiring passive treatment systems in the rule, industry fears that in many parts of the country, the active systems will be needed to meet the numeric turbidity limit. Further, industry argues concerns about liability will force the use of active treatment because passive treatment systems can vary in effectiveness based on circumstances, potentially putting construction site discharges in violation of the law.

EPA Technical Guidance for Federal Facilities Out

2009-12-09T08:17:00.000-08:00

New technical guidance from EPA came out last week. This particular piece applies to federal government facilities and puts more teeth to federal facility directives that have been out for a while. And while you might think that you don't deal with federal facilities, many municipalities and county offices actually do.

This guidance applies to "any building that is constructed, renovated, leased, or purchased in part or in whole for use by the Federal Government". It also specifies that the guidance applies to facilities with a footprint of greater than 5,000 square feet (sf) - this "includes all land areas that are disturbed as part of the project". This means it applies to the entire cleared construction area even if the structure is tiny or only remodeled.

Overall, about half the document is the "why" of LID. The rest is about implementing LID. A surprising amount of the implementation portion is dedicated to development of the design precipitation event, as discussed below.

The document provides two options for determining the volume of water to be retained on site. In the first option, the design storm (95% 24-hour event) must be fully retained on site. The document provides guidance on development of the 95% 24-hour event depth with several helpful examples.

In the second option, the post-construction hydrology must be equal to the pre-construction hydrology. It provides a site-specific approach to runoff control, rather than the first option which provides a more generalized approach.

Both options provide for a variety of methods to be used in converting rainfall to runoff. Direct Determination, TR-55, Rational Method, and SWMM are compared in the text.

The document provides some limited criteria regarding BMP design as well (Appendix A). It specifically addresses design of bioretention areas, with and without underdrains, using Horton's equation to assess infiltration and storage. Similar methods are used to assess green roofs and permeable pavers.

The main body of the document also notes cisterns and reuse as options for retention but addresses only infiltration BMPs in its analysis.

While I'm glad to see some guidance provided for federal LID development - there's still a lot to be desired in terms of design criteria. Given, federal facilities span the continent and the world, so its nearly impossible to provide criteria that would apply to every site. This document gives some basics for implementing three common LID techniques every stormwater engineer should have in their toolbox.

City of Broken Arrow Vets LID Practices Manual

2009-11-30T12:21:00.000-08:00

If you've not seen it yet, the City of Broken Arrow is in the process of vetting its Draft “Living Green Low Impact Development recommended Practices for Certification Manual ”. The following summarizes the Manual and is taken from the same:

Jeff Bigby, with the City of Broken Arrow, will be conducting two roundtable meetings on November 30 and December 3 . They are both open to the public! If you are interested in Broken Arrow's proposed policy, and want to hear what developers and consultants think, please come. The one at 11:30 to 1:00 on November 30 is a regular meeting of the BA Builders\Developers Council. The meeting from 1:30 to 3:30 on December 3 rd is a separate engineers\consultants roundtable entirely devoted to the LID program . They are requesting comments on the draft manual on a card to be distributed the meetings.

While certification programs like the one proposed by the City of Broken Arrow are used in other parts of the country, they are new to Oklahoma. To my knowledge this will be the first LID certification program in the state, other than the national LEED and Green Globes standards. (Correct me if you know otherwise!) As such, it stands to become a template for many other communities that are looking to implement similar programs.

Defining LID

2009-11-09T09:14:00.000-08:00

I've had several people ask me, after reviewing this blog, what exactly in Low Impact Development? And though we've attempted to shortly define the concept in our introduction, I liked this more lengthy description of LID from the Low Impact Development Center, Inc..

"LID is an innovative stormwater management approach with a basic principle that is modeled after nature: manage rainfall at the source using uniformly distributed decentralized micro-scale controls. LID's goal is to mimic a site's predevelopment hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff close to its source. Techniques are based on the premise that stormwater management should not be seen as stormwater disposal. Instead of conveying and managing / treating stormwater in large end-of-pipe facilities located at the bottom of drainage areas, LID addresses stormwater through small landscape (as well as process or structural, my addition) features located at the lot level.

LID controls can be incorporated into almost every section of urban and suburban environments including open space, rooftops, streetscapes, parking lots, sidewalks, and medians. This versatile approach can be applied equally well to new development, urban retrofits, and redevelopment / revitalization projects. LID provides numerous benefits and advantages over conventional stormwater management approaches. The major benefits of LID include being a more environmentally and economically sustainable way to address the adverse impacts of urbanization. By managing runoff close to its source though intelligent site design, LID can enhance the local environment, protect public health, and improve community livability."

More information from The Low Impact Development Center, Inc. is available from their website at www.lowimpactdevelopment.org.

New Public LID Projects for Tulsa, Norman

2009-10-01T12:22:00.001-07:00

Part of the American Recovery and and Reinvestment Act of 2009 (ARRA) included provisions for clean water projects in Oklahoma. All in all, Oklahoma was granted access to $31,662,100 in funds to improve water quality within the state. One of the stipulations of the ARRA is that 20% of these funds, or about $6.3MM, be used for "green" infrastructure projects.

Three projects that have been funded as part of the "green reserve" are an experimental green roof at the National Weather Center in Norman, Oklahoma, redevelopment of the dry pools into roof gardens at the downtown Tulsa City/County Library, and development of raingardens at the Tulsa City/County Library location in Sperry.

At the National Weather Center, a section of roof has been set apart for installation of a green roof system. The purpose of this roof section, as with many aspects of the NWC, is to educate the public. According the Oklahoma Water Resources Board, "Wide spread adoption of green roof technology remains absent in Oklahoma due to a limited local knowledge. This roof will be the first step to correct market deficiencies through knowledge creation and dissemination."

At the Tulsa City/County downtown library, we've all seen the "reflecting pools" located south of the library in the roof of the parking garage. The pools have been dry for as long as I can remember due to maintenance and structural issues and are something of an embarrassment, considering their location next to the Convention Center. The new green roof garden will be an asset and far more aesthetically pleasing.

The last LID project currently funded is installation of raingardens at the Sperry library. Sperry has had significant flooding issues in the past and the library continues to have a wet spot outside the front door. Why not a raingarden? This installation should address about 50% of the runoff from the facility and provide an educational opportunity as well.

Permeable Pavement for Oklahoma

2009-09-18T09:39:00.000-07:00

Over the past few years I've fielded a number of questions about the use of permeable pavement in Oklahoma. Permeable pavements are an alternative to conventional concrete and asphalt paving that allow for infiltration of stormwater through the pavement and into a subsurface storage area or drain. Recently, there have been some significant installations, including Chicago's U.S. Cellular Field parking lot consisting of 6 acres of interlocking pavers. Its important to look into the advantages and limitations for its use on local sites.

Initially, I began by looking into the ratings for permeable pavement provided by the EPA. EPA showed permeable pavements to have a failure rate of about 75%1,2. That was not encouraging. I looked into the studies behind these findings and found that they were from 1992. Well, a lot has happened in the LID world since 1992, so what about more recent studies?

My inquiries took me to states like North Carolina and Georgia, where water quality regulation is intense, and to the EPA's LID Development Center in Portland, Oregon. As you may know, some advantage of permeable pavement include:

* The lifespan of a northern parking lot is typically 15 years for conventional pavements due to freeze/thaw stress, which is also common in Oklahoma. Porous asphalt or concrete parking lots can have a lifespan of more than 30 years because saturation during freeze/thaw is reduced3.

* Permeable pavement transforms areas that were a source of stormwater runoff to a system that can reduce or eliminate runoff that would have been generated from traditional paving. Studies show stormwater retention rates ranging from 25-100% depending upon storm intensity. http://www.thewaterchannel.tv/index.php?option=com_hwdvideoshare&task=viewvideo&Itemid=53&video_id=349

* Permeable pavement can reduce the amount of pollutants in stormwater runoff and can address suspended solids (high removal rates), acid rain (some types effective), phosphorous (moderate removal), nitrogen (moderate removal), and metals pollution (best in vegetated systems).

So what's not to like? There are some drawbacks and limitations to use including:

* Permeable pavement is not recommended, or in some states even allowed, where surface soils are silt or clay. That's most of northeastern Oklahoma. Generally, permeable pavement is only recommended in areas with sandy surface soil, like the western part of the State, or where stormwater has been pretreated.

* Even when properly sited, maintenance requirements are critical for the success of permeable pavement. Proper maintenance includes vacuum sweeping or high-pressure water washing at regular intervals and inspections after each storm. If you can't commit to maintenance, there are better options.

* Porous pavement has reduced strength compared to conventional materials and isn't appropriate for applications with high volumes, high speeds, or heavy loads.

So how might permeable pavement be used in Oklahoma? Walkways, driveways, alleyways, and overflow parking are some options. And consideration should be given to preventing sediment from reaching the pavement, especially during construction, which can trouble a pavement system before it's even in use.

Finally, we have a responsibility to put our best foot forward for LID as these topics are being introduced in local communities, to hit the ground with practices we know have positive reproducible results. Who wants to hear, "More of my tax dollars gone to waste." again? The future of LID is in our hands!

1 Schueler, T.R., P.A. Kumble and M.A. Heraty. 1992. A Current Assessment of Urban Best Management Practices. Metropolitan Washington Council of Governments, Washington, DC.

2 J. Galli. 1992. Analysis of Urban BMP Performance and Longevity In Prince George's County, Maryland. Prepared for Department of Environmental Resources, Prince George's County, MD.

3 Gunderson, J., Pervious Pavements: New Findings About Their Functionality and Performance in Cold Climates, Stormwater, September 2008.

Canopy Economics - The Power of Trees

2009-09-13T20:57:00.000-07:00

During a news conference seven years ago this week, American Forests (americanforests.org) unveiled one my favorite studies - it showed that urban tree deficits were costing tax payers billions of dollars each year in air and water benefits. At that point, San Antonio, Texas, Charlotte, North Carolina and San Diego, California joined in as the first cities in the nation to take action to reverse the tree loss trend by incorporating tree cover data into their infrastructure database - considering trees on the same level as roads, bridges, and treatment plants.

The connection between tree canopy and stormwater may not be immediately clear. Trees reduce the volume of stormwater runoff by capturing some rain on their leaves and branches, which then evaporates back into the atmosphere. Other water infiltrates into the soil rather than running off the land, which must be managed. For example, San Antonio’s urban forest manages 974 million cubic feet of stormwater, valued at $624 million using a $0.64 per cubic foot value based on local engineering, construction, and land costs (Pape-Dawson Engineers).

The findings from American Forests showed that San Antonio had 27 percent tree canopy, seven percent open space, 64 percent impervious/bare urban land, and one percent water. However, if tree cover were increased from 27 to 35 percent citywide, 2.5 million pounds more air pollutants would be removed each year and stormwater runoff would be reduced by 103 million cubic feet during an average 2-year, 24-hour storm event. This service would be worth an additional $200 million in avoided stormwater facility construction.

"Flooding in San Antonio is an age-old issue," said Carol Haywood, a planner with San Antonio's neighborhood and urban design department. "Most folks think we need more concrete culverts to simply whisk the water away as fast as possible. We will use this green (infrastructure) data to model and demonstrate the ability of trees to perform a similar function without adding new concrete."

For its part, the City of Tulsa began a tree planting program in 2007, after that year's devastating ice storm. For comparison, that storm destroyed or damaged as many trees as Up With Trees had planted in its entire 30 year history. Since that time over 5,000 trees have been replanted, with a goal of 20,000 trees by 2010 through ReGreen Tulsa. The City, through its Tree Advisory Oversight Committee, seeks to increase tree canopy by 3% year over year through 2013. Overall, the American Forests recommend 35% canopy coverage in urban areas.

When municipalities are looking to control long-term stormwater infrastructure costs, it should be clear that canopy cover can be a key element. What if we designed for the 2-year 24-hour event with both concrete and canopy? How much less would taxpayers have to spend? And how much more we would enjoy our new public infrastructure.

Tulsa Raingardens: The Clyde Home

2009-09-04T05:00:00.000-07:00

This week we're featuring a local raingarden designed and installed by Tony and Jen Clyde in midtown Tulsa. I've been talking with Tony about his raingarden plans for a couple of years now. Their garden was planted in the summer of 2008, so I was curious as to how it was coming along. The answer is, "Great!", as you can see from these photos.

Tony designed this raingarden to address runoff from one section of their home encompassing about 170 square feet of roof. The location sits off the southwest corner of the home, in full sun, and is just off a stone sitting area. To begin his garden design, Tony performed a permeability test at the proposed raingarden location and found he had loamy soil with good infiltration.

The roof section selected for this garden has two downspouts that were disconnected from the storm sewer and rerouted, as shown in these photos. The first shows the downspout connection. The second photo shows the inlet into the raingarden.

Tony then began to dig out the raingarden. He excavated about 1.5 cubic yards of dirt, which has since been used in other yard projects. The garden is kidney-shaped, measuring about 4.5' x 10', or 45 square feet, and is 6" deep.

As an overflow outlet, a rut left by a utility truck was purposefully not filled in. The rut is barely noticeable in the grassy yard but functions regardless, channelling water out of the raingarden and into the street (and storm sewer) during high rainfall events. The overflow is located in the bottom left corner of this photo. Every raingarden needs an overflow.

The garden was then planted with facultative wetland plants - that is, plants that can handle periodic flooding. For this garden, Tony selected swamp milkweed, swamp verbena, sawtooth sunflower, and leadplant. The plants were obtained from Pine Ridge Gardens in Arkansas, which specializes in native plant materials. The plants were shipped directly to his home and cost about $110. To finish it off, Tony selected a good cypress mulch.

When I visited, there were numerous different species of butterflies and bees present. Although the plants were not chosen to attract pollinators, it is certainly effective. The garden looks like a natural, but planned, part of the landscape.

I asked Tony about comments from neighbors. He said the most common have been regarding the garden's attractiveness. But he did tell about one visitor who remarked, "You know your pond doesn't hold water." Some things take a while to catch on. :)

Dealing with Off-site Runoff

2009-08-25T20:23:00.000-07:00

I remember the first big storm that occurred after we moved into our current home: a river carved its way under the fence and through the newly sodded backyard. Where did it come from? A peek over the fence showed me something I hadn't noticed before. The adjacent backyard was a concrete slab, funnelling runoff from the house, outbuildings, and pavement through our yard. Granted, it wasn't my neighbor's fault. The problem had been there for decades and they inherited it just like us.

A number of people have similar experiences, though, when neighbors add on or developers substitute McMansions for bungalows. New guidance being developed by the City should address some of those infill issues, but what can you do about "run-on" short of legal action? In this case we looked at redirecting the river and decreasing its energy. And the application may give you ideas about how to handle your own off-site problem.

First, we talked with our neighbors about what we were observing. They made some changes to their yard, including switching two parking spaces to loose gravel. Tremendous! And it looks great too.

On our side of the fence, we used recycled concrete, which came from tearing out our own paved yard, to provide energy dissipation for the flow entering from the fenceline. Basically, that means putting something in the way of the stream to smack it around and is provided by the larger stone in the middle of the garden to the left. We then used the same materials to edge a planting bed along the fence and provided spaces between the concrete to allow water flow. The water then enters a horizontal gravel filter, made up of river rock, which dissipates the flow further and allows it to pass through the yard without being seen. The filter also acts as a walkway from the house to the play yard. On the downstream side of the walkway, I added a raingarden that is a few inches lower than the gravel bed.

Overall, the system dissipates the energy of the water entering the yard, filters the water, conveys it, and provides some infiltration. Afterwards, water exits into the alley. During high rainfall events, water flows through this system as well as overflows to the yard and a shallow lined channel directly to the alley.

I mentioned the design to someone recently and they asked "Isn't that just a walkway?" And I thought, "Yes, and No." I'll highlight again that stormwater controls don't have to look different, they just have to work different. And if it is mistaken for a walkway, great. That tells me its a job well done.

What's Up With Rats?

2009-08-13T07:26:00.000-07:00

It seems each time I talk about raingardens, someone has to ask about vermin. You know, squirrels without the cute fuzzy tails: rats and mice. The question is usually, "Do raingardens bring in vermin?". My standard answer is, "No". But after hearing it so many times, I decided to get some additional advice on the topic.

I talked with both a horticulturist and a biologist about this question. On my list were Jay Ross, Horticulture Curator at the Tulsa Zoo, and Stephanie Rainwater, a biologist at URS. Jay and Stephanie both noted that any garden with dense vegetation can provide a nesting area for all types of critters, from songbirds to cats to, you know. The key to what critters you attract is what food supply is nearby. If you have insects, you should get birds that eat insects, and so on.

In the public arena, a community might consider whether the garden is located near areas of animal feeding (advised or not), such as a duck pond or petting zoo. Likewise the residential homeowner should consider whether they leave dog, cat, or bird food where other animals can access it. In my own yard, I've found the compost heap to be a problem.

But are there features that make raingardens uniquely less prone to being used by vermin than other landscaping? The answer is yes. Raingardens are designed to flood - every time it rains. There aren't a lot of critters that will put up with being flooded on a regular basis - they'll pick somewhere else to nest.

So, what does all this mean? Raingardens should be less likely to house these unwanted guests than other types of gardens and landscaping, a fact that should encourage others to bring stormwater controls into their landscaping.

Rainwater Harvesting: How Much is Enough?

2009-08-07T06:51:00.000-07:00

This week's poll has to do with what people want to use rainwater collection for, whether it be watering lawns or running the commode. Even ambitious LIDers won't be using rainwater to wash clothes anytime soon b/c they don't have dual plumbing systems (potable/non-potable) in their homes. So that leaves most us looking at outside uses, watering the lawn and the like.

Rain barrels are becoming more and more popular. But it seems the minute most people put one in they want it bigger: a 55-gallon barrel doesn't go very far. How far you might ask? Well, I use a 55-gallon barrel for air conditioner condensate collection and am able to water my container plants for about week from one barrel. How much water do you need?

A traditional lawn needs about 1-inch of water per week during the summer. That's 0.623 gallons per week per square foot. (Sometimes I just call it a half-gallon per foot to make it easy.) If you have a lawn that is 20' x 50', that's 1,000 square feet of lawn. It would take 623 gallons of water per week. During the summer, let's say that it doesn't rain for a month. Over those four weeks your lawn would need 4 x 623 gallons = 2,480 gallons. If your lawn is bigger, you'll need more, maybe much more!

So, here's where reason kicks in. Are you ready for a 2,500 gallon (or larger) tank? Do you have the space? (A 2,500 gallon-tank is about 8 feet in diameter and 7 feet tall.) Does your neighborhood allow these kinds of appurtenances?

There are a number of factors to consider when evaluating "How Much is Enough?". Maybe for you it is a rain barrel to refill the fish pond, maybe it's finding out if the old cistern in the backyard still holds water, or maybe its having a system engineered for your specific needs. Whatever you decide, there's an opportunity every time the rain falls.

Kill Before You Till

2009-07-31T14:02:00.001-07:00

Is this a familiar sight? Bermuda grass is the bane of this gardener. Typically, directions for development of raingardens in native soil are to check permeability, clear the site, till in compost, and plant. But digging up sod in Illinois is different than removing the grass in Oklahoma.

Our primary grass seems to be Bermuda and it is invasive! Bermuda spreads not only by seeds but also by runners above and below ground. It can overtake over a foot of garden in a growing season. So, simply taking off the top layer of sod won't do. You have to kill it.

But how? I checked with the County Extension Office office for some direction. And their advice confirmed my anecdotal experience: Bermuda is tough stuff. You can try thermal sterilization of soil - putting down black plastic and allowing the sun's heat to kill everthing off. This kills the surface plants but doesn't address the deeper roots, which can be six inches or more below the surface. This also kills plants by depriving them of sunlight, but Bermuda can stay dormant under the soil for an extended period of time. I've also tried herbicides, which seem to work for a while, but Bermuda always seems to come back.

Bermuda, it seems, must be killed and killed again. They say up to 6 or 7 sprayings over time are necessary to really eradicate Bermuda from a proposed plot. And that takes planning ahead, about a growing season ahead, of when you want to plant.

And because it continues to spread from the outside, placing a good quality edge to 6 inches beneath the soil (not extending above the ground) will help minimize root intrusion. Surface runners take a hands-on approach. After all that, you should have a garden that is much easier to maintain. But it takes some time and planning (and a bit of grass-killer).

Traveling LID: Florida

2009-07-30T21:18:00.000-07:00

As you may have guessed, I have to make note of LID applications wherever we travel. We took a family vacation to Sanibel and encountered these raingardens in a small county park northeast of Ft. Myers. We went to watch manatees, which we didn't see, but we found multiple raingardens!

Much of Florida is condusive to bioretention, a fancy word for raingardens, because of its sandy soils and high infiltration rates. As you can see in these photos, the surrounding landscape has been graded to form a depression. This is where rainwater collects. Plants within the depression have been selected that can withstand periods of standing water, or inundation. And the water is allowed to infiltrate, or seep into, the soil.

Some of the things I liked about this park were the number and variety of raingardens present - in the parking lot, at the entrance, and scattered throughout. They also provided educational signs, which I don't have photos of. I also liked that they made use of a range of vegetation, from trees that look like they've been there forever (and they may well have) to bushes and groundcover. Its not obviously a stormwater treatment system but fits attractively into the overall landscape. Kudos!

Who Designs Raingardens?

2009-07-30T10:39:00.000-07:00

I was recently asked to come out and look over a new raingarden that had been designed by a reputable local landscape architecture firm. But I had been asked to take a look because it really didn't seem to the owner (a public entity) to fit the definition of a raingarden. Sure enough, the garden fit right into the profile of the slope, and did not provide a means of detention or opportunity for infiltration. I checked the design drawings which provided a planting plan with a note to set the garden six inches below the surrounding surface - not a bad start but not really a raingarden design. But it made me think again about a question I had received previously - who designs raingardens and why?

I checked with the Board of Professional Engineers for Oklahoma and the Board for Landscape Architects. And there is some confusion. Apparently there is joint commission that discusses and decides on such issues and I recommended that this could be a good question to consider. The feedback I received was that landscape architects should develop and stamp landscaping plans. But because LID features are designed, or should be designed, for stormwater collection, conveyance or treatment, the sizing and hydrology (how much water and where it goes) should be stamped by an engineer. Ah, interdisciplinary design. We get to all work together. Now, if we just would.