Columbia slough watershed

Impervious Surfaces within the Columbia Slough Watershed

In order to find all of the impervious surfaces within the Columbia Slough Watershed all of the streets, parking lots, buildings, railways and railyards were combined. This created an area that contained the impervious surfaces within the Columbia Slough Watershed. The removal of impervious surfaces can help with water runoff and minimizing the amount of harmful chemicals that can enter the Slough.

Impervious Surfaces within the Columbia Slough Watershed including freight areas

There are some types of surfaces that can be either impervious or pervious depending on certain metrics or criteria. In this case gravel was surface that could be considered both impervious and pervious under certain conditions. This analysis includes all areas that have gravel, which were mainly found in Freight Areas within the Columbia Slough Watershed

Green Roof Analysis of the Columbia Slough watershed

Another way that runoff can be minimized is through Green Roofs. Green Roofs can absorb rainfall, preventing runoff from entering the Slough. This analysis finds all of the buildings in the Columbia Slough Watershed that have a slope less than 15˚.