In the natural world, streams are free to flow where they will, driven by gravity and obedient to natural laws. In urban environments, however, streams often either “get in the way,” get modified by some means to accommodate land use objectives, or get ignored. In any case, urban waterways and their plant and animal inhabitants suffer, and so does the value of adjacent property.
Consider, for example, a developer with plans for a high-end residential community. In order to maximize his investment, the developer divides the land into as many building lots as possible. But there is a problem: the property sits in the drainage basin of a stream. The stream’s path creates many impediments to development; the way the plans are laid out, the stream will intersect streets in multiple locations.
Integrating the stream into the plan would make the development much more attractive, but would also extend beyond the financial means of the developer. The developer decides the best way to deal with the stream is to pipe it under streets and building lots until it exits his property to join a larger stream. In this process, the developer “straightens” the stream to minimize the amount of piping that will be required. There are also several tributaries to the stream that are in areas where the steepness of the terrain makes piping and backfilling too costly. In those areas, the developer decides to simply leave the tributaries alone.
The outcome is a primary stream with little replenishment and a steeper than normal gradient, many lots that are comprised substantially of fill dirt, and tributaries that are deprived of their natural drainage connections. In short order, these tributaries become little more than ditches that flood and cause extensive erosion to bordering properties during heavy rains. Over time, the tributaries may become deep, steep, and dangerous.
Restoring a stream is a complex and tricky business. It requires knowledge of the regulations, of course, but also expertise in understanding the relationships between land, surface water, and groundwater, and the assemblage of organisms that must be present to help maintain the health of the stream. Northwest Geoscience personnel are skilled in the use of the Rosgen stream classification system and proposing solutions that accurately match characteristics that are appropriate to the stream type.
If your property or neighborhood is suffering with a low quality stream, a place that is an eyesore and a potentially unsafe place for the neighborhood children to play, give us a call. We’ll gladly visit your property, discuss your goals, and create a restoration plan that will meet them. We have developed a methodology for creating photorealistic images of how the stream will look once the restoration is complete, so you won’t have to close your eyes and guess how it will look.