Investigation of Pollution in Chiltipin Creek - Pollution Abatement in Region V

Oil wells in the Plymouth and Sinton fields contributed 32 per cent of the 254,000 barrels of waste emptied into Copano Bay during 1962. Sixty-four per cent of samples collected from the wells' effluents contained oil in excess of 25 ppm., the maximum allowed by the Texas Railroad Commission. The portion of Chiltipin Creek that collects the waste from these two fields contained oil 59 per cent of the time. Most of the skimming pits in Sinton Field are too small and too poorly constructed and maintained to retain the waste oil efficiently. Most of the separators in Plymouth Field are well constructed and maintained, but several wells dispose excessive amounts of waste and separators alone will not retain the waste oil. The operators are working with chemical treatment to remove the waste oil. Taft and Midway fields disposed 67 per cent of the total volume of wasate entering Copano Bay. Oil was present in 36 per cent of the samples taken from the effluent. Only 12 per cent of the samples collected in the drainage ditches prior to disposal into Chiltipin Creek and Copano Bay contained oil. This reduction is attributed to additional skimming by a separator in the Taft drainage ditch and a 50-acre lake in the Midway ditch. Most of the oil lost into Chiltipin Creek is filtered out of the water by debris and creek banks. Ten per cent of the samples collected at the mouth of Chiltipin Creek contained oil. This oil disperses into Copano Bay, clings to clay particles and settles, covering 25 per cent of the bottom west of the causeway. However, there is no increase in oil concentration over the previous year.