The cities of Sugar Land and Missouri City, as well as several private well owners, are actively working alongside dozens of local service providers to meet groundwater reduction requirements set by the Fort Bend Subsidence District. As homes and businesses move to surface water service, utility bills are expected to reflect a flat fee increase in January 2014.

Groundwater is pumped from local wells that draw from several aquifers around the city. Surface water sources are typically from natural rivers and creeks that require a treatment process.

The FBSD's mandate was approved in September 2003 and requires certain areas of the county to convert to 30 percent surface water by 2014 and 60 percent by 2025. The mandate was based on the state legislature's requirement to reduce groundwater pumping that causes subsidence—the lowering of the land-surface elevation—which can lead to flooding and damage to infrastructure, said Mike Turco, general manager of the FBSD.

"We have seen everything from parking lots and subdivisions become [damaged] to seeing wells collapse from subsidence," he said.

Subsidence

About 60 percent of the water used in Fort Bend County is from groundwater sources. The FBSD mandate divides the county into three parts: Area A, which includes the northern and eastern parts of the county where governing entities must adhere to the issued mandate; the Richmond/Rosenberg sub-area, which is required to meet the 30 percent surface water requirement by 2016; and Area B, which consists of the southern and western parts of the county where no requirements are set.

Area A has historically seen upwards of 3–4 feet of subsidence as a result of groundwater pumping, specifically the areas closer to Houston, Turco said.

Turco said that the FBSD will likely take another look at setting requirements for Area B in coming years, but with a sparse population living in a large area, governing entities are expected to have a difficult time delivering surface water to area residents.

"There is a certain amount of water that can be taken from reservoirs without resulting in subsidence," he said. "Wells will be used for peak purposes and emergency backup. What it comes down to is there is not enough surface water for us to go to 100 percent. The district understands that, and we work to make reasonable requirements."

Surface water treatment

Sugar Land and Missouri City have implemented Groundwater Reduction Plans that outline projects to help convert groundwater to surface water.

The city of Sugar Land's new $69 million surface water treatment plant began pumping and delivering surface water to residents in November 2013. The treatment plant is the city's largest capital improvement project ever completed, city officials said. The plant can pump and treat up to 9 million gallons of surface water per day, which allows the city to meet the 30 percent groundwater reduction requirement by 2014.

Raw water rights along Oyster Creek secured through a contract with the Gulf Coast Water Authority supply the treatment plant. Treated surface water is pumped to two of the city's seven groundwater pumps and is mixed with treated groundwater before being distributed.

"Mixing the two types of water before distribution ensures our customers will receive the same high-quality, superior tasting drinking water they are accustomed to having flow from the tap," said Jessie Li, assistant director of water utilities.

In February 2012, Missouri City began delivering surface water to Sienna Plantation residents through its newly constructed surface water treatment plant, which has the capacity of treating about 10 million gallons of raw surface water per day from the Briscoe Canal—an offshoot of the Brazos River.

"Missouri City is unique in the fact that we have more than 20 MUDs both in the city and in the city's extraterritorial jurisdiction," said Robert Upton, utilities manager for Missouri City. "Several years ago, the city, the county and the MUDs all got together to form this partnership in order to meet both the mandate set forth by the Fort Bend Subsidence District and the needs of the community."

The city has converted about 23 percent of its groundwater use to surface water, and will move closer to the 60 percent requirement as master-planned communities continue toward build-out.

"As development continues, we are working to meet the requirements of the Fort Bend Subsidence District," Upton said. "At that point, our pumping capacity will need to be increased. It makes the most sense to convert to surface water use in areas where development is happening."

The Sienna South and Riverstone communities are expected to bring thousands of new residents to the city, and both Missouri City and Sugar Land are working with local MUDs to begin offering surface water to residents as they come in.