Know Your Water
When you turn on your faucet, where do you think your water comes from? For many people, the answer is simple: the sink, the shower, or the garden hose. But the real answer goes much deeper, literally. Here in Bastrop and Lee Counties, 100 percent of our municipal water supply comes from groundwater. That means the water we use every day comes from underground aquifers beneath our feet. These aquifers are one of our region’s most important natural resources, and understanding them is the first step in protecting them. So, how well do you know your water?
Groundwater is water stored underground in layers of sand, gravel, sandstone, and other porous materials called aquifers. Think of an aquifer like a giant underground sponge. Rainfall slowly seeps into the ground and fills the tiny spaces between soil and rock particles. Wells are then drilled into these aquifers to access the water below.
Our region relies on several aquifers, including the Carrizo-Wilcox Aquifer and smaller aquifer systems such as the Sparta, Queen City, and Yegua-Jackson. These underground formations did not appear overnight. They were formed over thousands to millions of years as ancient rivers, streams, deltas, and even shallow seas deposited layers of sand, silt, clay, and gravel across Texas. Over time, pressure and natural geologic processes transformed those sediments into the aquifer systems we depend on today.
One of the easiest ways to picture our groundwater systems is to imagine a layered cake beneath the ground. As you go deeper underground, you move through different layers, each with different materials and different water-bearing characteristics. Some layers contain sand and sandstone that can store and transmit groundwater. Other layers are made mostly of clay and act as confining layers that separate one aquifer unit from another.
The Carrizo-Wilcox Aquifer, one of the primary aquifers supplying water to our region, is not just one single underground layer. It is made up of several geologic units stacked on top of one another. In our area, these units include the Hooper, Simsboro, Calvert Bluff, and Carrizo formations. Each unit has different geologic characteristics, depths, water production capabilities, and recharge rates.
Some of these units are more productive than others, meaning they can yield larger quantities of groundwater to wells. Others may recharge more slowly or contain different water quality characteristics. Understanding these differences is an important part of groundwater management and long-term water planning for Bastrop and Lee Counties.
One of the most important things to understand about groundwater is that recharge takes time. Aquifer recharge happens when rainfall infiltrates into the soil and slowly moves downward into underground formations. But not all rainfall becomes groundwater. Some evaporates in the Texas heat, some runs off into creeks and rivers, and some is absorbed by plants before it can ever reach an aquifer. That is why healthy landscapes and watersheds matter.
Many people hear the word “watershed” and immediately think it refers only to rivers or lakes. But a watershed is actually all the land area where rainfall drains to a common body of water, such as a creek, stream, river, or bay. One way to imagine watersheds is like a set of Russian nesting dolls. Small watersheds fit inside larger watersheds, which fit inside even larger river basins.
For example, rain that falls in your backyard may first flow into a roadside ditch, then into a small creek, then into a larger stream or river, and eventually into a major river basin before ultimately reaching the Gulf of America. Each smaller drainage area is called a subwatershed because it is part of a larger watershed system. To find you watershed you can go to: Texas Watershed Viewer Website.
These connections matter because everything that happens on the land can impact water downstream. Soil erosion, fertilizer runoff, litter, oil, chemicals, and other pollutants can all be carried by stormwater into creeks and rivers. At the same time, healthy landscapes with native vegetation and healthy soil can help slow runoff, filter pollutants, and encourage rainfall to soak into the ground where it can help recharge aquifers.
That is why water conservation and responsible land stewardship are so important here in Bastrop and Lee Counties. Every drop we conserve helps reduce strain on our aquifers and supports the long-term availability of groundwater for future generations. The water beneath our feet has taken thousands of years to accumulate. Understanding where it comes from and how it moves helps all of us become better stewards of this shared resource. You cannot protect what you do not understand. And that is why knowing your water matters.