Guillen G2010-02-152010-02-151993http://hdl.handle.net/1969.3/23289518-527Dissolved oxygen and selected nutrient trends in the Houston Ship Channels (Texas Water Commission (TWC) segments 1007, 1006 and 1005) during the period of 1969 through 1990 were evaluated using non-parametric time series analysis. Surface and/or bottom concentrations of dissolved oxygen, ammonia nitrogen, nitrate nitrogen, orthophosphate, and total phosphorus from selected stations were evaluated. These data indicate that dissolved oxygen levels have increased in the Houston Ship Channel over the last 20 years when adjusted for seasonal variation. During this period of time point source wastewater loading (lb/d BOD) from domestic and industrial sources has decreased. Resulting decreases in phosphorus compounds and ammonia nitrogen, and increases in nitrates as a result of enhanced nitrification, have also occurred. Increased aquatic life use in the HSC has been documented by other TWC studies as a result of these increasing trends of dissolved oxygen. It is highly probable that the increased dissolved oxygen levels observed in the HSC are due to increased regulation and enforcement by state and federal agencies, increased facility compliance, and subsequent decreases in wastewater effluent loading and bypasses. These results illustrate the importance and application of a well designed monitoring program for the purposes of tracking the effectiveness of water quality managementAmmoniaCoastal engineeringManagementMonitoringNitratesOxygenPhosphorusTexasTime series analysisWaterWater pollutionWater qualityWaterway transportationCONF