Gray Merriam | May 08, 2019
Spring is flood season. We all try to protect our homes against the rising water, but the level is higher each year. We need to fight the current flood but we also need to slow or stop that increase in flood levels in coming years. Here are some basics to consider:
Much ongoing discussion is about filling and piling sandbags. Sandbags attempt to block rising waters downstream where the river or creek is big.
The river is big downstream because it has been filled by all the medium-sized and small creeks and rivers further upstream. The big river that the sand-baggers are fighting contains all the water that has run off the entire basin drained by that river – its watershed.
Between 66 and 80 percent of the area of a watershed, where all the rain falls and the snow melts, is drained by little creeks and flow paths – the headwaters.
If the flow in those little creeks is slowed and there are many little wetlands to catch and hold some of the water, the big river downstream will be kept from cresting over those sandbag walls.
Thoughtful care of those upstream head waters areas can be as simple as protecting little wetlands and keeping natural vegetation on as much of the headwaters area as possible. Vegetation slows runoff. Keep the water on the land. This approach can reduce future flood peaks. Walls of sandbags can only hold against this year's flood.
The basic approach is simple: apply your management effort as far upstream as possible, even if you live away downstream. Climate change is not the only cause of floods. A healthy watershed can reduce floods.