A Landscape Architect’s Role in Erosion, Sediment and Storm Water Issues
By Russell Adsit, FASLA, Executive Director, International Erosion Control Association
“Many landscape architects don’t want to take on preparation of storm water plans, because they are too complex. They would rather let the contractor or engineer take that responsibility. But most landscape architects do prepare grading and drainage plans, planting design and irrigation design. They can take on erosion plans as well.”—Russell Adsit, FASLA
Some aspects of landscape architecture can be intimidating. Erosion preparation is one of them. However, I am going to show you erosion control is easier than you may think, and it can be included in the services you provide.
Too few landscape architects see the unique role they can play in erosion, sediment and storm water issues. They even minimize the impact good design can have on site stability and sustainability. Last time I checked, the major programs of landscape architecture include courses in soils, vegetation, hydrology, weather patterns, drainage and grading and slope stabilization. Somewhere in there should also be some sort of visual inspection ability even if it includes a site checklist when looking at a construction site. These are some of the basic tools that we can build upon.
If we have a construction project that did not involve rainfall, we could finish sooner, costs would be less and we would only have to deal with wind erosion. Stormwater is the source of most water on construction sites. Erosion is the source of sediment and if we properly control erosion, we can minimize sediment issues on a project site. Most landscape architects know this, but are reluctant to apply this knowledge to preparation of an erosion and sediment control plan. One reason is that the storm water pollution and prevention plan is not a typical static design plan. It has to “move” with the progress of the construction site. This includes construction measures as well as the permanent establishment of the vegetation or surface. Many professionals who have specialized in this work realize that this might initially be seen as a challenge but this really is a great opportunity. They are engaged to visit the site on a regular basis, they are tasked with making adjustments as the weather or other conditions change the site or circumstances appear that require more effective measures to control storm water, erosion and sediment. There are temporary as well as permanent measures employed in the process, so it is never simply a matter of establishing grass or vegetative groundcover. It becomes a moving target during construction factoring in the changing weather, construction progress and seasonal dynamics. When the project is complete you get to inspect it for final acceptance and signoff on the project.
How many of you are frustrated by the lack of contract engagement to allow you to visit the site on a regular basis? You say, “Okay, but what about all those regulations we have to know?” Don’t you have to know all the planning and zoning regulations for any community you operate within? And are you telling me that those are so similar that once you know one, you can apply it to all? At least in the storm water, erosion and sediment control arena, the rules are based upon the Clean Water Act and while each state usually develops its own “rules” or construction general permit, the similarities are refreshing when compared to all the differences you will find in planning, zoning and other municipal regulations.
Other dynamics you will deal with in properly designing storm water systems include the erosion process, peak flow, time of concentration, rainfall intensity, slope and even watershed definitions. Didn’t you learn these in school and don’t you already deal with this in good design practice? Oh, and you already know how to read a plan, draw a plan and read contours to determine the direction, concentration and erosion potential of the site because you also looked at your soil maps or conducted soil tests on the site. Slow it down, spread it out, sink it in. Easy as pie, right? Now, go out and apply what you already know and get better involved with your projects and protecting the environment. And if you need to know more technical data, the International Erosion Control Association is here for you.