Stormwater Management for Residential Clients An Interview with Vallari Talapatra

Nina Koziol

Flash flooding on May 14th this year was reported throughout northern Illinois, according to the National Weather Service. Four inches of rain in Chicago set a new record as multiple storm systems moved through the area. Elsewhere in the state, creeks and rivers overflowed onto roadways. The state climatologist’s office reported that May was wetter than the 30-year normal and the 25th wettest May on record. It wasn’t a surprise to Landscape Architect Vallari Talapatra of Eco Scapes in Wheaton.

“It’s not a new concern, but a rapidly growing one,” Talapatra said. “Every year we seem to hit a new record for rainfall. That, coupled with more hardscape, larger patios, bigger garages and larger homes, increases the run-off amount and that’s what’s leading to a huge storm-water management problem in residential properties.”

Talapatra’s presentation on Stormwater Management at iLandscape this year was filled to overflow capacity. “I’ve been doing landscape design for 24 years now. In the first decade, water runoff was not an issue. During the second decade, there were a few problems and now I’m seeing problems that I’ve never seen before.” We talked to her recently to find out more about what landscape designers and contractors can do to help mitigate the problem.

With the record May rainfalls, what type of problems have you seen? Almost every phone call this year involved a need to manage water runoff. Landscaping has become secondary to fixing drainage issues. Many of my clients are in DuPage County since I’m based out of Wheaton and teach at the Arboretum, but I have north shore clients as well. (continued on page 22)

Before

(continued from page 20) When there’s a home addition, it can create a big problem for the neighboring yard. Detached or really big garages that are two-stories tall also contribute to runoff. Driveways are a classic example of a contributing problem. The homeowner may go from a one-car garage to a three-car garage and bigger driveway. If I can, I try to persuade them to use permeable pavers or decomposed granite for the driveway. That may be one of the options, but it’s also about budget: It’s not always possible to do it all at once. For example, in one project, we did permeable pavers in a small section of their long driveway. They loved it so much that they allocated the money to the entire driveway in a few years. You can also line a driveway with permeable pavers and leave the center in asphalt. My point is that it does not have to be all or nothing. If a particular client doesn’t have the resources to pave the entire surface, I try to persuade them to do at least some of it.

Are there areas that are more prone to flooding? Yes, some neighborhoods are more prone to flooding, including those that don’t have good stormwater management planning or border communities that don’t have it. Sometimes, historic districts can have more issues than a new development, where hydrology calculations were part of the site planning. It’s not an issue where cities have incorporated runoff volume calculations and they are mitigating problems with retention or detention ponds. Some neighborhoods are encouraging infiltration basins or rain gardens for home owners that are building larger homes. These are the communities that have the least number of stormwater issues. Prairie Crossing ( http://prairiecrossing.com) in Grayslake comes to mind. You can see how the whole community has been designed in a way that each house drains into a retention/detention basin and each lot also has swale along the curbside. It’s a systematic way of solving the larger issue of stormwater management.

Why is flooding worse now? It’s worse now because natural areas are not protected or conserved as they should be. It’s not just about the small scale proble — expanding patio sizes from 200 square feet to 450 square feet—you have to zoom out and look at the larger context. One of the effects of urbanization is taking over wetlands, which are sponges, and putting in paved surfaces, roads and houses over them. Coupled with that is everyone’s desire to have larger outdoor spaces and you can see how the water doesn’t have a place to soak into the ground.

The entire Chicago area was a swamp/watershed area and we tend to forget that. I have learned that one has to understand and respect the hydrology of a place. At the start of every project, I try to find a hydrology plan of the larger area to investigate the water flow and water table, but there’s often nothing available or updated because there’s been so much development. You have to construct your own watershed plan to figure out the lay of the surrounding land. (continued on page 24)

After

Before

A dry creek bed captures water that might otherwise affect the home’s foundation before and after The most common way to mitigate water issues is to design French drains and dry creek beds. Sometimes they are tied to dry wells, too. Often, they may also be a part of a rain garden or a bioswale. I recommend the use of rain barrels but usually we leave it to the homeowners to install them. Reducing lawn surfaces and giving my clients more garden area is another technique that helps with infiltration. A young family with little kids wants maximum lawn space and would not want large beds or rain gardens, so I have to come up with something else, like permeable pavers.

I did about five large installations this year and the first one had huge water issues. When we started the project we had to regrade the entire yard. Sometimes it’s as simple as fixing an underground storage system. We’re storing the water and releasing it much more gently (continued from page 22)

Where do you start on a residential site with flooding problems? One of my guiding principles is that a good design will only happen if you are able to “read the land.” With so much development there’s usually no existing benchmark. What’s the water table? There’s no way to know. I’m talking about the Landscape Architect or designer who is trying to find the documents. You need to look at drainage patterns, zoom out and look at the grading, the contouring for the entire subdivision. Having that knowledge helps, but I don’t go to the village hall for that information. I look at Google Maps. Try to track the flow of water not just on your client’s property but around it. You have to inspect the entire block to see where the flow is coming from and record it. I sometimes ask my client to take photos or videos property. After What are some of the methods used to manage stormwater on site?

the grading. But on one site, we had to put in to see how much water is coming into the

and slowly. We’re starting another project (continued on page 26)

(continued from page 24) using big storage tanks. We never ever had to do that before. Previously, we were able to solve those problems with French drains that were dug 18 to 24 inches deep.

About 10 years ago, the Arboretum contacted me to teach a workshop on rain gardens. I have noticed that every spring we have had more participants, which corroborates the idea that the need for stormwater management for homeowners is growing. The philosophy behind any landscape design solution to solve drainage issues will have to incorporate these three things: Slow, Soak and Cleanse. For me the “cleanse” part is critical. All the runoff is so highly polluted—and that’s the issue—it’s not a visible impact to clients, but you have to have a way to explain to them why it’s necessary. Why is it important that the migratory birds and water fowls downstream need the protection?

What other types of mitigation efforts might help? Dry creek beds, bioswales and planting more trees, can soak up gallons of water, like 6000 gallons a day. And roof gardens—they’re huge. Roof gardens are very rare in homes and they shouldn’t be. In Holland, they do it very successfully. I would love to see more suburban homes embracing roof gardens.

Some municipalities look at a brand new house and determine the amount of paved surface on the lot. They have a table for how much permeable surface, rain garden or infiltration basin is needed. Rain gardens can sometimes occupy more than half the backyard. You find a way to have creative solutions—not just doing a rain garden but using a bioswale or a group of trees, rain barrels, and so on—use different methods. There is so much paved surface and so much roof on some sites, you’d need a large infiltration basin, which is like a rain garden. This is why you may have to combine a few different methods so that the rain garden area is not overwhelming the landscape.

Client Relations “Reading the land” and “reading the client” are the two prongs in my landscape designs. I’m passionate about balancing the wishes of my clients and the right thing to do. I try to do this in a very gentle way so that it’s almost like it’s their (continued on page 28)

(continued from page 26) solution, not mine. The gentle nudging to using the more environmentally friendly solution continues with sending them pictures of something I’ve done or something on Pinterest. A lot of people use the idea books on my Houzz account. All of my solutions are based on a more holistic design. My undergrad was in architecture and my whole approach is very heavy on design. I create a bold, cohesive plan, and try to convince clients in a very gentle way. One of the best ways to persuade clients is to actually have them visit something that I have installed. Since my clients are mostly through word of mouth, sometimes they may have seen one of their friend’s gardens that I did and that helps.

The EPA mantra for stormwater runoff management is “slow it down, spread it out, soak it in.” What are some suggestions you have for doing those three things? For slowing the water—gravel, rain barrels, storage tanks, flows and do something with it—make it part of my design.

even plants. I encourage landscapers to do a shade garden— if the yard isn’t big, do a smaller tree like a vernal witch hazel or a Hawthorn. Woodland grounds are sponges and one of the ways you can maximize your capacity and reduce lawns. If the client doesn’t have young children, one of the ways would be to use larger beds, like a layered border, sometimes even 8 to 10 feet wide. Homeowners can be scared of that, but it can be really attractive. Sell it as a layered landscape with textures. Show them pictures. You have to sell the look first. You have to make sure they like it. You’re actually creating groundwater recharge. I try to convert each of my clients into feeling good about this. I go through my whole spiel with them that by doing this, you’re impacting everyone down stream. Rain gardens and dry creek beds are amazing—I love doing them. Some landscapers do underground systems, but I like to expose my systems. I like to study nature, see how water

you need woodland plants—ferns, sedges, ginger. That’s

What resources would you recommend to landscapers? The Illinois Department of Natural Resources has really good guidelines for residential properties at https://www2.illinois. gov/dnr/cmp/Documents/StormwaterManagement.pdf.

You can see Talapatra’s work at https://eco-scapesinc.com.

Bluestone chips allow run off to slowly permeate the soil below