Guide to Release Levels
Any body of water can be unsafe at any level. Use caution and judgment at all times. THESE ARE RECOMMENDED LEVELS ONLY.
- Up to 500 cfs — Recreational
- 500 – 750 cfs — Challenging
- 750 – 1200 cfs — Strenuous
- 1200 – 3000 cfs — Extreme caution; tubing not recommended
- 3000+ cfs — Dangerous; guided rafts suggested
For more information on water recreation and location of businesses in the WORD district, click HERE.
What Determines the Minimum Flow on the Guadalupe?
Canyon Reservoir below 909 msl
A drought is considered the day after any period of forty five (45) consecutive days during which the inflow to Canyon Reservoir averages less than 90 (cfs), and shall continue until the reservoir level returns to 909 feet above mean sea level.
During this time GBRA releases flows according to senior downstream water rights holder only.
Canyon Reservoir exceeding 909 msl
The lake is a flood control reservoir with a holding capacity designed to catch flood waters before they do damages downstream. This means that the lake level will fluctuate year round as water flows in and out of the reservoir.
During this time the US Army Corps of Engineers controls the outflow of Canyon Lake. Changes to the releases depend in response to rainfall or other factors.
Canyon Reservoir at 909.0 msl
During this time GBRA typically matches the inflow to Canyon Lake.
The following factors are considered:
The GRTU-GBRA Contractual Trout Protective Flow
The settlement granted the following trout protective flows: “GBRA agrees that the minimum daily release from Canyon Reservoir for each day during the months of May, June, July, August and September of each calendar year during the term of this Contract will be not less than the release specified below for that day (averaged over 24 hours), if and only if Canyon Reservoir reaches an elevation greater than 909.0 feet m.s.l. for any length of time prior to that day during the period between January 1 and September 30 of that year.”
The FERC Minimum Flow Requirement
Beyond the Contract, the first regulatory requirement for minimum flows came from the Federal Energy Regulatory Commission (FERC) Requirement. This requirement is the result of the GBRA operated hydro-electric plant at the base of Canyon Dam. Article 405 states: The licensee shall discharge from the Canyon Dam Project a continuous minimum flow of 90 cubic feet per second, as measured immediately downstream from the project powerhouse to protect and to enhance fish and wildlife resources In the Guadalupe River.
The flow may also be reduced to not less than the Inflow to the reservoir during periods of drought. Additionally, at times other than during periods of drought when the inflow to the reservoir is greater than 90 (cfs), the licensee shall, at a minimum, discharge from the project whichever is least (a) the inflow to the reservoir or (b) a continuous minimum flow in accordance with their schedule
The Texas Commission on Environmental Quality Requirement
The TCEQ mandated minimum flows are contingent on the “Base Storage Level” of Canyon Reservoir being above 909.0 msl on any day on, or after, January 1 of the calendar year. It ends when the “Base Storage Level” is below 909.0 and inflows to Canyon Reservoir average less than 90 cfs during any period of 45 consecutive days. The Base Storage Level is a ‘virtual’ measurement and cannot be determined by physical gage, but by GBRA’s spreadsheet. The TCEQ minimum flow from Canyon Dam is a “pass-thru” requirement.
In addition to the “Pass Through” requirement, there is a “Diversion” requirement that could also impact the release from Canyon Dam. “Water may be diverted from the Guadalupe River at any point downstream of it confluence with the Comal River and upstream of the U.S.G.S. Gauging Station at Gonzales, Texas to the extent such diversions do not reduce the measured stream flow at Gonzales below the specified amounts. If the diversions reduce the flow at the Gonzalez Gage below the above rates, then an additional flow (see the monthly flow values from the Pass Through table) must be allowed to remain in the river to the “salt water barrier”.
GBRA-Comal County Contract For Recreational Flow
Comal County arrived at a contract with GBRA in which GBRA agreed to request a deviation in the Corps of Engineers flood control release procedures from Canyon Lake. The lake is in flood whenever the elevation exceeds 909.0 msl. On a year by year basis, the request must be made to the Corps. The deviation allows the lake between 909 and 910 to have a “recreational pool” where the floodwaters are released at a minimum of 250 cfs, or higher, depending on the inflow to Canyon Lake. The deviation is generally in effect from April through August. The two wettest months are May and June, so this provides additional protection to the trout fishery.
Texas Water Law Requirements
Water rights must be passed through Canyon Lake for more senior water permit holders. In Texas, first, in time is first in right. So if a water right exceeds the 1956 or 1999 permit dates to Canyon Lake, any water flowing into Canyon Reservoir must be “passed through” the reservoir and to the more senior permit. These flow amounts are generally insignificant.
For more information visit:
Current Lake &
- Guadalupe River @ Spring Branch (Upper): 618 cfs
- Guadalupe River @ Sattler (Lower): 385 cfs
- Guadalupe River @ New Braunfels: 529 cfs
- Canyon Lake Reservoir: 910.76 ft
For more flow rates, visit the USGS website.