Every year we hear of significant flooding in many communities across America and see the television images of homes flooded and destroyed. We also hear that underground water resources are being depleted in many communities because of increased demand for underground water by agriculture and growing communities. This article proposes a solution that many communities could implement that would take care of both of these issues at the same time.
To often communities rely on levee systems to keep water out – especially if they live along a river system. Natural flood plains disappear because population centers grow and expand into them. Farmland and pasture lands that were annually flooded by overflowing rivers have been replaced by subdivisions in many areas. Relying on levees for protection will eventually lead to the devastation of the community because once the level is breached or fails, the water will quickly fill in all the areas that the levee was built to protect. Once the water breeches the levee – it has no natural way to return to the river system as the levee blocks it from returning to the river.
What has to happen is that communities must plan for all of the excess water to go somewhere – away from populated areas. When cities along a river build up levees for the purpose of walling the water out, the river level simply goes up as the river continues downstream. At some point downriver the levees can no longer contain all of the additional water that the river is carrying, because the natural flood plains are gone and levees keep it in the river channel proper. The ideal solution is for cities to relocate away from the river channel and restore the system of natural flood plains. However, this isn’t feasible in most instances.
Whenever dams can be used to retain water in a reservoir behind them, this can be a good solution. The reservoir provides recreation for the population and can be very scenic; however, the environmental movement to remove dams has grown specifically in an attempt to return river systems to their natural state. The problem for population centers is that river flooding is one of the basic natural conditions of any river system. It is as natural as the wildlife and ecosystems that grow up along a riverbank.
The best solution that would work for everyone is a system where rivers are allowed to return to their natural state of flooding, without damaging population centers. The way to do this is to first designate parcels of rural county land to be designated wildlife floodplain areas and for the county to either purchase this land directly or set up a system for landowners to deed the areas as wildlife conservation areas while retaining ownership. The county then needs to provide a natural system that allows for excess river water to flow to these rural areas without damaging any property.
Constructing this natural overflow system is not very difficult. In essence it works as a relief valve when the river is stressed by excess water. Dry channels or dry river beds need to be dug away from the river itself at an elevation that is above the natural water level of the river. This dry river bed continues to a point where there is enough area to construct a retention basin of a significant size that the water can flow into. It has to be rural enough to not threaten another population center away from the river. An abandoned gravel pit or wildlife area is an ideal choice. Once the retention basin fills with water it allows the water to naturally seep back into the ground to replenish the water table.
These overflow dry river channels will have berms around them of raised earth that was excavated from the channel or basin. Once constructed, they are replanted and allowed to return to a natural state, similar to the natural areas around them. Wildlife and a natural ecosystem will follow, creating a wildlife habitat that returns the land back to its most natural condition. During times of flooding, the river rises and some of the excess water is carried away to fill the retention basin, and when necessary overflows into the conservation area. If every county along a river system did this where feasible, the entire river system would be relieved of the excess water capacity and the existing levees would easily hold the remaining water.
Communities need to plan and coordinate together throughout the entire river system to allow the excess water a natural place to go. These retention basins could actually be large dry lakebeds, available to fill when necessary. Wildlife would prosper, the land would be kept in a natural state and population centers would be less threatened from the devastation of major flooding. To do otherwise is foolish and to invite significant loss from flooding in communities across America.