As a designer one tool I often use is Autodesk / Autocad. I design House & Site plans that insure the retaining of sediment. Aquatic life in Georgia is rapidly decreasing due to the amount of construction that is going on in the south. This is due to the lack of sediment control on a property when building. The toxins find their way into the creeks and rivers which then wind their way into the larger lakes, thus killing the fish. The process of studying the topography on a piece of land, then taking the appropriate steps to keep chemicals and building materials from washing off of the construction site is a major part of what I do day in and day out. Retaining walls, and sediment fencing, placed in the correct places, keep most of these harmful substances on the property where they can be properly disposed of (usually).
Another interesting part of my work is calculating the square footage of all the impervious areas on a site (roof, driveway and any concrete) that will cause rain water runoff. I then provide several ways to capture rain for recycling in these areas. The rain water is recycled into the individual homes using things like underground "flo wells". These wells store and filter the water to prepare it for general usage again. In some cases the water is filtered into a cities water recycling facility. However this is dependent upon the county that I'm working with.
To most peoples surprise, there are many counties in Metro Atlanta that require these steps and more. Not all though.