lower more saline bays nearer the Gulf 

 harbor the adults (fig. 29). 



Figure 29. — Average size (carapace width) of blue crabs 

 In relation to salinity In the Galveston estuary. 



Charles R. Chapman, Acting Project Leader 

 Wallace L. Trent 

 Cornelius R, Mock 

 Edward J. PuUen 

 Robert D. Ringo 



EFFECTS OF ENGINEERING PROJECTS 



The developnnent of water resources for 

 maximum use is being accelerated, largely 

 in response to increased Federal participation. 

 The need for the Federal Government to enter 

 this field to provide irrigation, flood control, 

 navigation, hydroelectric power, municipal 

 water supply, and other functions was recog- 

 nized mainy years ago. Such Federal agencies 

 as the Corps of Engineers, Bureau of Reclama- 

 tion, eind the Soil Conservation Service have 

 carried out and continue to initiate water- 

 development programs. State governments, 

 municipalities, and private orgamizations also 

 are active in this field. 



The value of estuaries as nursery and feed- 

 ing grounds for many connmercially important 

 species of fish and crustaceans is well known 

 to biologists but usually not to the planners 

 and developers. Because more than 90 percent 

 of the fish taken in the Gulf of Mexico are in 

 some way dependent upon estuaries, the need 

 to review and evaluate water use asid develop- 

 ment projects and to devise appropriate meas- 

 ures for protecting, rehabilitating, and im- 

 proving the estuarine nursery areas is clearly 

 evident. 



Laboratory personnel are cooperating and 

 assisting the Division of River Basin Studies 

 of the Bureau of Sport Fisheries and Wildlife 

 to evaluate effects of engineering projects on 

 commercial fisheries in Texas. We also help 



formulate specific recommendations for proj- 

 ect modifications that will ensure the least 

 damage to and, when possible, improve the 

 value of estuarine fishery resources. It can be 

 demonstrated, occasionally, that the adverse 

 effects from construction projects on the 

 fishery resources clearly overbalance the 

 benefits to other interests. 



Recognizing the above problems, project 

 personnel during the past year and under the 

 present system of coordination with the Divi- 

 sion of River Basin Studies reviewed and 

 appraised the plans for 435 private projects 

 that could potentially affect estuarine fishery 

 resources. Sections of 57 Bureau of Sport 

 Fisheries and Wildlife draft reports pertaining 

 to construction projects were also reviewed. 

 The number of projects and reports reviewed 

 increased more than one -third in the last 

 year. 



During the latter half of fiscal year 1966, 

 considerable effort was devoted to coordination 

 of studies on the Corps of Engineers Texas 

 Coast Hurricane Protection Project. The pro- 

 posed plcins would provide for a combination 

 of seawalls, levees, and tide -control structures 

 along the Texas coast to provide hurricaine 

 protection. The hurricane study covers five 

 areas as follows: Galveston Area, Corpus 

 Christi Area, Matagorda Bay Area, Sabine 

 Lake Area, and the Laguna Madre Area. 



The location of the seawall for the Galveston 

 Bay Area has not been decided, but the follow- 

 ing four alignments between High Island and 

 Freeport are being studied: Plan A--the sea- 

 wall would be 305 m. offshore in the Gulf of 

 Mexico; Plan B--the seawall would be con- 

 structed on the Gulf beaches; Plan C--the 

 seawall would follow the existing highways on 

 Bolivar Peninsula, Galveston Island, and 

 Follets Island; and Plan D--the seawall would 

 follow the existing Gulf Intracoastal Waterway 

 alignment. Each alternative would include a 

 surge-control structure in San Luis, Bolivar, 

 and Rollover Passes (fig. 30). 



A fifth and different alignment is also being 

 considered in the event Plans A through D 

 cannot be justified economically. This plan 

 would include a surge-control structure and 

 levee across the bay between Smith and Eagle 

 Points that would divide upper and lower 

 Galveston Bays. The levee or seawall would 

 extend along the north shore of East and West 

 Bays. The separation of the marshes bordering 

 East and West Bays from the bay proper poses 

 a real problem. This plan jeopardizes both 

 fish and wildlife habitats, including two wildlife 

 refuges. The loss of this much marsh could be 

 disastrous to the fishery resources of Galves- 

 ton Bay. A solution must be found. 



The Corps of Engineers has constructed 

 two scale models of the Galveston Bay system, 

 each having their particular functions and 

 capabilities. One, a small-scale surge model 

 covering the area between High Islamd and 



28 



