Are We Asking the Correct Questions?
This is an image from the National Weather Service for the estimated precipitation of the past seven days. A few of the stream gauges in Texas and Louisiana have experienced water levels rising sufficiently to establish a new flood of record. Though this is a lot of rain over the course of a few days, it's not uncommon. Before the media start claiming this is the storm of the century or the millennium, I wonder if we're asking the correct questions.
While changes in weather patterns may result in this type of storm event, it doesn't mean that the impacts should be extreme. Are we doing enough to understand how the outcomes of an event like this are related to changes in land cover and alteration of water conveyance within a watershed?
As people affected by this type of an event continue to respond that they've never seen a flood like this, or it's never flooded in a particular area, or no one ever told me I needed flood insurance, shouldn't it be the responsibility of the local government to evaluate changes in the watershed so that people and property are protected?
Wouldn't it make sense for the local government to track changes in land cover and run hydrologic models every 2-3 years to understand how those changes will create new areas that will be subject to flooding?
Emergency Management Specialist at University of Tennessee at Chattanooga
8 年This brings to mind a story of my small home town of Hamlin, WV. During the WPA days a bridge was built over the river below town. The road was low and the bridge sat on piers on either side of the small waterway. Every time the river would rise the road would flood cutting off access from that side of town. In the mid 70's an "improvement" was made. The old bridge came down, the road was made straight and it was placed on a causeway above the flood level. The river was diverted through two 16 foot diameter culverts under the causeway. The first time the water rose it filled the culverts with debris that in previous floods would have been washed across the flooded road. Once blocked, the causeway acted as a dam which flooded the town above to levels never seen before. Later surveys showed the water level up stream was about 12 inches above the level of the causeway which was, amazingly enough, covered by about the same amount of water. All of the "shade tree engineers" in town knew exactly what had caused the problem and some had even predicted it. Today we would blame it on "climate change".
Empowering people to make informed hydrology and weather decisions for a resilient tomorrow.
8 年Good Questions Mark! I completely agree that we need to evaluate the land use in the entire watershed and not simply study the more populated regions. I saw a demonstrations last summer by the USDA using their Rainmaker Simulator. https://www.youtube.com/watch?v=z9K9idBcJLY It shows how different range management scenarios/farming practices affect soil absorption rates and shows water and sediment runoff as well as subsurface water movement. The Tilled/bare ground (sample to the far Left in the Youtube demonstration) clearly shows lower absorption rates, so more water and sediment run of . When I saw this demonstration, a light bulb went off that we not only need to study building strategies, bank improvements and storage containment for flood mitigation but we also need to be evaluate our farming and ranging strategies in our watersheds.
Director, Compliance and Risk Management
8 年I think you're absolutely right and that this is the direction we need to be heading. All land changes for development must be approved through the local government, so shouldn't they have the responsibility to inform the community, or at least study what impacts these changes will have elsewhere? I think so. It'll be interesting to see how urban & regional planning efforts keep up with the changing physical world and what changes we implement to adapt to a new "normal".