EFFECTS OF ENGINEERING PROJECTS 



The importance of estuaries as breeding, 

 feeding, and nursery grounds for many com- 

 mercially important species of fishes, crus- 

 taceans, and mollusks is well known to the 

 fisherman and to the professional biologist. 

 About 98 percent of Texas commercial land- 

 ings are of species in some way dependent 

 on estuaries. 



The estuary represents a habitat type known 

 as an ecotone--a "buffer zone" or zone of 

 transition--between the fresh water of the 

 river system and the salt water of the sea. 

 The characteristics of such a habitat are 

 readily susceptible to change through natural 

 or artificial alteration. Among the latter are 

 many and varied forms of water development 

 projects, such as impoundments on rivers and 

 streams, dredging and channel construction, 

 and real estate land fills in the estuaries. The 

 cumulative effects of these projects upon the 

 estuaries and associated fish production are 

 likely to be extensive. 



Though our present knowledge about the 

 effects of such projects upon fishery resources 

 is somewhat meager, it is important that we 

 review project plans and advise the appro- 

 priate agencies what they might expect. In 

 Texas, our personnel are working directly 

 with representatives of the Bureau of Sport 

 Fisheries and Wildlife, the Texas Parks and 

 Wildlife Department, and other Federal and 

 state agencies. Under this system of coordina- 

 tion, during fiscal year 1965 we reviewed 

 plans and proposals for 326 construction 

 projects in estuarine waters, 40 of which were 

 adjudged to have potentially serious detri- 

 mental effects upon estuarine fishery re- 

 sources. Drafts of 40 Bureau of Sport Fisheries 

 and Wildlife reports evaluating the effects of 

 construction projects on fish and wildlife re- 

 sources also were reviewed. 



Most engineering projects that we reviewed 

 for their possible effect upon fishery re- 

 sources in Texas are located near large popu- 

 lation centers. About one-third of the projects 

 are planned for construction either in the 

 Galveston estuary (fig. 35) or on rivers and 

 streams that supply fresh water and nutrients 

 to the estuaries. After discounting those in- 

 volving mineral development, almost half of all 

 bulkheading-fill and dredging- channelization 

 projects were slated for this estuary. As the 

 human population of the Gulf coast increases, 

 more engineering projects can be expected in 

 other areas as well. More than 90 percent of all 

 projects reviewed were privately sponsored. 



Project personnel spent considerable time 

 during the year on nnajor projects in Texas 

 (table 9) as well as other areas along the 

 Gulf coast that required special study. We 



o,B 



Figure 35,--Location in the Galveston estuary of privately 

 sponsored projects reviewed during fiscal year 1965. 

 Does not Include locations of seismographlc operations. 



helped the Louisiana Wild Life and Fisheries 

 Commission and the Division of River Basin 

 Studies, U.S. Bureau of Sport Fisheries and 

 Wildlife, review the results of the Mississippi 

 River-Gulf Outlet Project so that the size 

 of project-caused changes onadjacent estuaries 

 and marshlands could be determined. Much 

 effort also was spent revising and completing 

 the estuarine fisheries section of the Fish and 

 Wildlife report on the Bureau of Reclamation's 

 Texas Basins Project. 



Many projects that involve diversion of 

 fresh waters of rivers for municipal, indus- 

 trial, and agricultural purposes are detri- 

 mental to the estuaries. The Corps of Engineers 

 Lower Colorado River Project, however, may 

 divert surplus fresh water from the Colorado 

 River into eastern Matagorda Bay. This body 

 of water used to receive the discharge of 

 the Colorado River, but the river delta has 

 formed across the estuary so water is now 

 discharged directly into the Gulf of Mexico. 

 The major supply of fresh water is now re- 

 ceived by Lavaca Bay, a part of the Matagorda 

 estuary. 



37 



