WHAT IS A WATERSHED?

A watershed is an area of land that drains into a water body such as a river, lake, or bay. Watershed boundaries are defined geographically as a ridge or line of highest elevation towards areas of lower elevation; the bayou or lake is where the surface and subsurface waters collect and flow towards the watershed outlet. Watersheds can be small or large, and most are interconnected, working together as a system. A watershed system eventually drains into the ultimate water bodies—the oceans.

Louisiana has 12 major watersheds or river basins composed of several hundred smaller sub-watersheds.

You're Sitting in a Watershed Now

Everyone resides in a watershed.
Every place on the earth is a part of a watershed. Homes, farms, ranches, forests, small towns, big cities and more can make up watersheds.
Some cross parish, state, and even international borders.
Watersheds come in all shapes and sizes - some are millions of square miles & others are just a few acres.
There are many living and non-living things in watersheds.
Watersheds are constantly changing.

A watershed is like a bathtub. The watershed outlet - the mouth of a pond, lake or river- is the tub's drain. The watershed boundary is the tub's rim. The watershed's drainage system consists of a network of rivers, streams, constructed channels, stormdrains, wetlands, and the underlying groundwater.

A Watershed has 3 Primary Functions

It captures water from the atmosphere. Water infiltrates the soil and percolates downward. Several factors affect the infiltration rate, including soil type, topography, climate, and vegetative cover. Percolation is also aided by the activity of burrowing animals, insects, and earthworms.
It stores rainwater once it filters through the soil. Once the watershed's soils are saturated, water will either percolate deeper, or run off the surface. This can result in freshwater aquifers and springs. The type and amount of vegetation, and the plant community structure, greatly affects the storage capacity of a watershed. The root mass associated with healthy vegetative cover keeps soil more permeable and allows the moisture to percolate deep into the soil for storage. Vegetation in the riparian zone (the biologically distinctive area that borders the waterfront and acts as a protective buffer between land and water) affects both the quantity and quality of water moving through the soil.
Water moves through the soil and is ultimately released into coulees, bayous, and the ocean. Slow release rates are preferable to rapid release rates, which result in short and severe peaks in stream flow. Storm events which generate large amounts of run-off can lead to flooding, soil erosion and siltation of waterways.

Ultimately, the moisture will return to the atmosphere by way of evaporation. The hydrologic cycle (the capture, storage, release, and eventual evaporation of water) forms the basis of watershed function.

Your Watershed is Important

Our watershed is a dynamic and unique place. It is a complex web of natural resources - soil, water, air, plants and animals. Yet, everyday activities can impact these resources, ultimately impacting our well-being and economic livelihood.

Healthy watersheds are vital for a healthy environment and economy. Our watersheds provide water for drinking, irrigation and industry. Many people also enjoy lakes and streams for their beauty and for boating, fishing and swimming. Wildlife also needs healthy watersheds for food and shelter. What we do in the watershed has far reaching effects. These effects are what we can see, the physical effects and what we think, our attitude towards what is right and wrong.

Understanding the history and development of the Bayou Vermilion watershed is important because after thousands of years of stability, the watershed has dramatically changed in the past century. In geological time this century of change is a like a nanosecond.

Why has it changed so much in such a short time? A hundred years ago, there were not that many people living in Acadiana, so there were fewer homes and more marshes, prairies and forests. Today lots of people reside here and need a place to live and there are less natural places.

What will this area be like fifty years from now? Most likely more people will live in Acadiana and they will need homes. So we need to plan for more people to live here and make choices about the future of our community. Most of the questions and answers are not right and wrong, but involve tradeoffs.

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