As of January 1, 1987, the surface-water data-collection network in Texas included 376 continuous streamflow, 76 continuous or daily reservoir-content, 34 gage height, 16 crest-stage partial-record, 8 periodic discharge through range, 33 floodhydrograph partial-record, 9 flood-profile partial-record, 36 low-flow partial-record, 46 daily chemical-quality, 19 continuous-recording water-quality, 84 periodic biological, 17 lake surveys, 162 periodic organic and (or) nutrient, 3 periodic insecticide, 42 periodic pesticide, 19 automatic sampler, 141 periodic minor elements, 130 periodic chemical-quality, 78 periodic physical-organic, 22 continuous-recording three- or four-parameter water-quality, 34 periodic sediment, 22 continuous-recording temperature, and 30 national stream-quality accounting network stations. Plate 1 shows the location of surface-water streamflow or reservoir-content and chemical-quality or sediment'stations in Texas. Plate 2 shows the location of partial-record surfacewater stations.

This index shows the station number and name, latitude and longitude, type of data collected, and the office principally responsible for the data collection (table 1). An 8-digit permanent numerical designation for gaging stations has been adopted on a nationwide basis; stations are numbered and listed in downstream order. In the downstream direction along the main stem, all stations on a tributary entering above a main-stem station are listed before that station. A tributary entering between two main-stem stations is listed between them. A similar order is followed in listing stations on first rank, second rank, and other ranks of tributaries. To indicate the rank of any tributary on which a gaging station is situated and the stream to which it is an immediate tributary, each indention in the listing of gaging stations represent one rank. This downstream order and system of indention show which gaging stations are on tributaries between any two stations on a main stem and the rank of the tributary on which each gaging station is situated. On plates 1 and 2, the 8-digit station number is abbreviated because of space limitation.