People decided around the pioneer times that wetlands were wasted space and good for nothing else besides being drained and used for agriculture (1). They supposedly posed a health risk by harboring mosquitoes, and were difficult to navigate through (1). In 1846 one of the first major wetlands altering projects began in Horicon Wisconsin. The town needed a sawmill and decided to dam a river leading out of the "Great Marsh of the Winnebagos". Over time the dam caused the water level to rise in the marsh and it turned slowly into a lake. At first this was a welcome reprieve and residents used the lake for recreational activities. However, landowners sued the sawmill in 1869 after a flood, and won. The dam was removed and water drained freely once again. The townspeople, now suddenly without a lake, sat around debating what to do with the recently drained land. As they debated, something interesting was happening in the marsh. Birds that had previously passed over the lake suddenly started landing there and staying. Ducks began to migrate through the marsh and started nesting. A few years after the dam removal, duck hunters began reporting 500,000 ducks hatching each spring and flocks of geese covering the sky (2). Something that originally had no value now was important to a large group of people. The land was later acquired by the state and is now a wildlife refuge. Wetlands conservation has been the cornerstone of game bird protection, and vice versa. However, it has not been until recently that cities are catching on and realizing their use for flood prevention.
In an effort to reduce flash flooding, cities build rainwater swales that collect water during high rain events. These swales have a porous bottom that allows the water to re-enter the ground slowly over the next few days time. Most of the swales are often bare looking, just a grassy bowl on the side of the road. However, taking it one step further, wetland swales can be created to solve a variety of problems. Manufactured wetlands are a huge gigantic step in the right direction for wetlands conservation. They can attempt to bring back some of the benefits of natural wetlands, as well as provide recreational opportunities.
Houston is uniquely located in a low lying bayou/ marsh ecosystem and has dramatically changed the landscape with urbanization. It comes as no surprise that it regularly suffers flooding events on a large scale, even in the absence of hurricanes. A notable wetland restoration project in Houston is the Sheldon Prairie (4). Filled in for agriculture use, Sheldon prairie was excavated following some historical records and allowed to fill in with water. Native plants were planted by students and volunteers from TAMU and local schools. The project was finished in 2009 and now is an excellent wetland habitat.
With some grant money flowing in from the gulf oil spill only time will tell if more wetland restoration projects get funded. Luckily it seems that the policy of draining or filling wetlands has slowed or ceased in some areas. The US has operated on a “no net loss” policy of wetlands implemented by George HW Bush in 1988 (5). This policy has been in effect and maintained by every president since and acts as a barrier for farmers and developers when draining wetlands. Even with this policy in place, lack of enforcement and encroachment of development has led to a slow decline in wetlands between 2004 and 2009 (6). The biggest threat to wetlands seems to be climate change, which has damaged coastal wetlands the most (6). If we learned anything from the Horicon Marsh story it is that wetlands must be measurably valuable to people in some way. In cities they are not just habitats for birds, they exist for flood prevention and water purification. Maybe it’s time to beef up this policy to a “net gain” and reclaim some of the 100 million acres that have been lost.
Sources for this post
1. Dahl, T.E., and Johnson, C.E., 1991,Wetlands--Status and trends in the conterminous United States, mid-1970's to mid-1980's: Washington, D.C., U.S. Fish and Wildlife Service, 22 p.
2.The History of Wetlands, USGS https://water.usgs.gov/nwsum/WSP2425/history.html
3. Why are Wetlands important, EPA https://www.epa.gov/wetlands/why-are-wetlands-important
4. Sheldon Prairie Restoration Project https://tcwp.tamu.edu/wetland-restoration/sheldon-lake-prairie-wetland-restoration-project/
5. No net loss regulations https://www.law.ufl.edu/_pdf/academics/centers-clinics/clinics/conservation/resources/no_net_loss.pdf
6. Status and Trends of Wetlands in the Conterminous United States 2004-2009 https://www.fws.gov/wetlands/documents/Status-and-Trends-of-Wetlands-in-the-Conterminous-United-States-2004-to-2009.pdf