glossary of terms

Conservation Capacity: The capacity of a reservoir's conservation pool; if the reservoir is shared with another state or country then conservation capacity refers only to the portion that belongs to Texas.
Conservation Pool: Conservation pool refers to water in a reservoir that lies above the dead pool and below the maximum normal operating level. For reservoirs with a flood storage function, the maximum normal operating level also corresponds to the bottom of the flood pool. When a reservoir's conservation pool is full, the reservoir is considered full. (TWDB Report 48, TWDB Report 126)
Conservation Pool Elevation: The elevation of the top of a reservoir's conservation pool. The term is used interchangeably with maximum normal operating level. Some reservoirs in Texas are operated at a level that differs from the top of a reservoir's conservation pool or maximum normal operating level. This level is referred to as normal operating level (for example, Lake Granbury and Possum Kingdom Lake).
Conservation Pool To Dam Top: The vertical distance between top of conservation pool and dam top.
Conservation Pool To Maximum Design Water Level: The vertical distance between a reservoir's conservation pool and maximum design water level. See maximum design water level below.
Conservation Storage: The amount of water present within a reservoir's conservation pool. Conservation storage is sometimes referred to as normal or multipurpose storage (USACE 2018). If reservoir operations are based on a normal operating level, conservation storage is calculated based on the normal operating level. If the reservoir is shared with another state or country then conservation storage refers only to the portion that belongs to Texas.
Dead Pool: Dead pool refers to water in a reservoir that cannot be drained by gravity through a dam's outlet works. Water that is in the dead pool is not considered part of conservation pool.
Elevation-Area-Capacity Table: A table that relates water surface elevations with volumes and surface areas for a reservoir. These relationships are obtained from either from original design documents or from a hydrographic survey of the reservoir. A single reservoir may have multiple tables that reflect changes in reservoir conditions due to processes like sedimentation.
Emergency Spillway: Spillway for water to flow past dam into downstream channel to reduce reservoir storage for dam safety / flood protection purposes. Sometimes, a spillway can serve both water supply and flood protection purposes. Also, see spillway below.
Flood Height Percent: The ratio of water level above conservation pool to flood space upper bound above conservation pool expressed as percentage. The flood space upper bound is the maximum design water level, or dam top when this level is not available.
Flood Pool: Flood pool refers to water that lies above the conservation pool in reservoirs with flood storage function. A reservoir's flood pool is used to regulate floodwaters. Some reservoirs have seasonally-varying flood pools.
Freeboard: Additional dam height above top of flood pool intended to provide extra safety.
Height Above Conservation Pool: The vertical distance between a reservoir's water surface elevation and the top of the conservation pool. Negative numbers indicate how far below 'full' the reservoir is, while positive numbers indicate how far above the top of the conservation pool the water surface is.
Height Above Dead Pool: The vertical distance between a reservoir's water surface elevation and the bottom of storage pool.
Maximum Design Water Level: A designed water level. By design, when water is below this level, water pressure will not cause dam to slide or fail.
Percent Full: The ratio of conservation storage to conservation capacity expressed as a percentage.
Reservoir Capacity: The total amount of water that a reservoir can safely hold. It is the sum of dead pool, conservation pool and flood pool.
Reservoir Storage: The amount of water present in a reservoir.
Sediment Reserve: Part of reservoir capacity that is allocated for storage of sediment that is expected to be deposited over a certain period of time. Sediment reserve and dead pool storage are not mutually exclusive.
Service Spillway: Spillway for water to flow past dam into downstream channel for water supply purposes. See spillway below.
Spillway: (Mostly) a trough-like structure over a dam for water to flow past dam into downstream channel.
Surface Area: The area of the top surface of a reservoir's body of water.
Water Surface Elevation: The elevation of the top surface of a reservoir's body of water.