Lake Granbury Water Levels: Who Controls the Pool and What It Means for Your Dock

Who Controls the Water and Why It Matters

Lake Granbury's water levels are managed by the Brazos River Authority, which built the lake in 1969 through the DeCordova Bend Dam on the Brazos River. The lake's existence is fundamentally tied to a water supply agreement with TXU Electric Company — BRA sells water that goes to a natural gas-fired steam electric power plant on the reservoir itself and to the Comanche Peak Nuclear Power Plant near Glen Rose. These are the lake's primary customers. Recreational use is a secondary benefit that BRA accommodates but does not optimize for.

That mandate matters for buyers because BRA's operating decisions — how much water to release through the DeCordova Bend Dam's 16 Tainter gates, when to restrict outflows, and how aggressively to draw down the pool during drought — are driven by water supply obligations, not by the desire to keep the lake at full pool for boating and fishing. The BRA explicitly states this in its permit materials: "Lake Granbury is a water supply reservoir and water levels will fluctuate; therefore, an approved permit does not guarantee access to water for recreation." This is not boilerplate legal hedging. It is an accurate description of the lake's operating reality.

Full Pool: 692.7 Feet Above Mean Sea Level

BRA considers Lake Granbury full at 692.7 feet above mean sea level. The DeCordova Bend Dam's Tainter gates have their top measured at 693 feet msl, providing a tiny margin of storage above the stated full pool before spillway conditions. The 16 Tainter gates, each measuring 36 feet wide by 35 feet high, allow BRA to release up to 433,000 cubic feet per second when fully open — the dam's safety release capacity in extreme flood conditions.

Under normal conditions, BRA manages the reservoir to stay as close to 692.7 feet as inflows and water supply obligations allow. In wet years with adequate Brazos River inflows, the lake holds at or near full pool for extended periods and the recreational experience is excellent. In drought years — and the Brazos River watershed experiences significant multi-year drought cycles — the lake can drop several feet below full pool, exposing shallow areas, reducing cove depth, and leaving some dock structures in water too shallow for deeper-draft boats.

Drought Reality: What Happens Below Full Pool

The 2011-2012 drought was the most severe in modern Texas history and affected the Brazos watershed significantly. Lake Granbury dropped well below full pool during that period. Cove areas that hold 4 to 6 feet of water at full pool can drop to 2 to 3 feet in a significant drought year — workable for kayaks and small flat-bottom boats but problematic for larger pontoons and runabouts that need 2.5 to 3 feet of clearance under the hull. Some canal-finger properties and back-lake areas in shallow coves effectively lost usable waterfront access during the worst drought years.

The pattern from BRA's Elevate Realty comparison data (October 2025): "In coves like Indian Harbor or portions near Harbor Lakes, a fixed pier can feel tall if the shoreline recedes." Floating docks provide more margin in drawdown years than fixed piers — a consideration worth discussing with a local dock builder before deciding on new dock construction type.

The lake does not have a scheduled seasonal drawdown the way some TVA-managed lakes in Tennessee do. BRA does not deliberately lower the pool each fall for maintenance — it is a supply reservoir, not a hydropower or flood control facility with planned draw-down cycles. But drought-driven level drops are real, recurring, and can last multiple years. Buyers evaluating specific properties should ask specifically about the water depth at the dock at full pool and at drawdown conditions, and should walk the shoreline at the current lake level to assess what low-water conditions look like for that specific lot.

The Cove-Lot vs. Open-Water Distinction

This is the most practically useful piece of water-level information for buyers choosing between Lake Granbury properties. Open-water lots on the main body of the lake maintain adequate depth through all but the most extreme drought conditions because the main channel holds depth even when the overall elevation drops. A dock in 15 feet of main-lake water at full pool has 11 or 12 feet at 3 feet below full pool — still fully functional. A dock in 5 feet of cove water at full pool has 2 feet at the same drawdown — a boat stuck on the bottom.

Before purchasing any Lake Granbury cove or canal-front property, ask the seller what the water depth is at the dock at current lake level, and what it was during the lowest point of the 2011-2012 drought if they were owners at that time. If they were not, ask neighbors or check the TWDB historic reservoir level data for Lake Granbury. The Texas Water Development Board maintains historic lake level records at waterdatafortexas.org. Pulling up the historical record for Lake Granbury and identifying the lowest recorded levels in the past 20 years takes about three minutes and tells you exactly how far the lake has drawn down in the worst conditions on record.

Monitoring Current Lake Levels

BRA provides current Lake Granbury level data through its website at brazos.org under "Water Levels." The Texas Water Development Board at waterdatafortexas.org provides the same data with historical context and percentage-of-full-capacity tracking. USGS gauge data for the Brazos River upstream of the lake is also publicly available and provides early signal on incoming inflows during rain events.

For buyers considering purchase during a drought period, checking the current lake level against historical full pool and confirming water depth at the specific property's dock is an essential due diligence step. For buyers purchasing when the lake is at or near full pool, the drawdown scenario is still worth researching — it is the condition you will experience in the periodic dry years that are a normal feature of the Texas climate cycle.

What the Dam Release Schedule Means Below the Dam

The DeCordova Bend Dam's gates control not only reservoir elevation but also flow in the Brazos River below the dam — relevant for buyers considering riverfront properties on the Brazos below the dam, including the Pecan Plantation area and riverfront homes in the sections of Hood County downstream of the dam. BRA releases water downstream based on its operational needs, and these releases can change river stage quickly. For boating, fishing, and dock use on the river below the dam, BRA's downstream notification system provides advance warning of significant release changes — sign up through brazos.org.

On the lake itself, dam releases affect outflows rather than levels — when the lake is above full pool during heavy rainfall, BRA uses the Tainter gates to control the pool. Residents in low-elevation areas downstream of the dam need to be aware of BRA release schedules during major storm events; BRA operates a downstream notification sign-up on its website for exactly this purpose.

The Permit Disclosure About Water Access

BRA includes a specific disclosure in its Lake Granbury permit materials that every buyer should internalize: "Lake Granbury is a water supply reservoir and water levels will fluctuate; therefore, a permittee may need to modify pumping equipment in order to maintain continuous access to the water supply. Nevertheless, access is not guaranteed in all circumstances." While this is stated in the context of the residential water permit, the underlying principle applies to dock use as well. BRA's operating mandate can result in water levels that make your dock temporarily inaccessible for deep-draft boats in prolonged drought. The lake is a managed resource, not a natural lake with predictable stable levels. The best Lake Granbury buyers are the ones who understand this going in rather than discovering it during Year 3 of a drought.