Applied Geomorphology

Jim Warren was called to this site because there was a huge problem with erosion caused by runoff from a storm drain. A small creek flowed to the north of the property owners house, but when the storm drain was installed this creek episodically became a raging river (Figure 1). This raging river, began to incise itself into the hill on which the house sat threatening to compromise the very foundations of the house.

Figure 1 - Aerial Photograph showing the area of incision.

Jim and his crew decided to install a series of step dams in order to control the influx of rainwater on the site (Figure 2). These step dams would slow the water down and hold enough of the water to allow a slow release of excess flow and thus minimize the effects of the erosive water.

Figure 2 - The series of rock dams installed help slow the storm drainage down

The reason that the storm water was so successful at eroding the property was the fact that this land used to be the bottom of the lake during the last ice age. The glacial lake sediments, mostly clays, are pretty tough to weather. Beneath these clays are glacial tills which are very easily weathered (Figure 3). Once these tills are exposed and weathered, they are quickly eroded creating huge furrows into which the lacustrine clays will slump greatly exacerbating the situation.

Figure 3 - This furrow has been created by the runoff from the house. If this is
allowed to continue the homeowner will have another huge problem on their hands.

The homeowner with the help of Jim Warren and his company successfully fought back against civic engineering gone wrong. Because of the geomorphic know-how of Jim and his crew, the property owners were able to sue the city and win enough of a settlement to pay for the constuction of the step dams.

By Jake McDonald

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Last Update: December 18, 2007
Webmaster - Jake McDonald