Problem Statement - Relocation of the GIWW 



Authorization for the present dimensions of the GIWW in Matagorda Bay is 

 contained in U.S. Congress (1939). It is beUeved that the original waterway exited the 

 land cut opposite Palacios Bay and proceeded to Port O' Conner in a much more northerly 

 route than diat occupied at present. This original route would have been the most direct 

 and would have taken advantage of deeper water in the north portion of the bay. The 

 GIWW in Matagorda Bay was relocated in 1944 in support of military activities at Camp 

 Hulen, which was located near the city of Palacios. The relocation of the waterway to the 

 south was probably done on local discretionary authority. Authorization to relocate the 

 channel back to its pre- 1944 position is contained in U.S. Congress (1962). 



Presently, the GIWW crosses the MSC about 13,0(X) ft northward of the bayward 

 side of the MSC entrance, and there is substantial ship and barge traffic at that 

 intersection. Significant shoaling as well as swift currents are also present because of the 

 close proximity of the intersection to the MSC entrance. The current has been reported 

 by the Matagorda Bay Pilots Association to be exceptionally difficult on flood tide, 

 which they estimate reaches 7 knots (approximately 3.5 m/sec).' According to a 1994 

 letter sent to the Galveston District by the U.S. Coast Guard (USCG), there were 44 

 groundings and 382 aids-to-navigation discrepancies near the intersection in 1994.^ The 

 combination of rapid shoaling, strong wind, and strong tidal current greatly increases the 

 likelihood of grounding by towing vessels. Because of the strong current flowing 

 through it, the MSC may be one of the few locations along the coast of Texas where tidal 

 force dominate wind force. However, wind-induced currents, as well as the wind acting 

 on high profiles of ships and empty barges, are also significant factors for navigation in 

 all Texas coastal waters, including at the MSC-GIWW intersection. 



The GIWW section located northeast of the MSC-GIWW intersection that runs from 

 sta 6(X)-hOO to 615+00 requires maintenance dredging each year, and barge groundings 

 occur frequently along this stretch. Sundovra Island, an artificial island created from 

 dredged material, lies near the intersection, east of the MSC and south of the GIWW, and 

 the high-frequency dredging section runs along the north side of the island. The island is 

 a successful and prominent "Beneficial Uses of Dredged Material" site that serves as 

 habitat for the endangered brown pelican. The island is prone to erosion, and it is only 

 through near-aimual noiuishment and shore protection over some of its perimeter that it 

 remains. The mechanism of the erosion is examined in the present study. It will be 

 shovm in this report that material eroded from the island is a significant contribution to 

 shoaling in the GIWW. 



The Galveston District, the USCG Marine Safety Office, the Matagorda Ship Pilots, 

 and the waterway towing industry have raised the possibility of moving the GIWW 

 northeastward. The new intersection of the MSC and GIWW would be located about 

 7,000 ft northward of the present intersection and about 20,000 ft from the bayward side 

 of the MSC entrance. Potential benefits to relocating the GIWW northward are as 

 follows: 



^ Personal communication, 2 December 1998, Mr. Larry Robinson, Pilot, Matagorda Bay Pilots 

 Association. Mr. Robinson has been piloting ships in Matagorda Bay since 1981. He stated that 

 the current in the MSC has become stronger over the years, which he attributes to the gradual 

 closure of Pass CavaUo. 

 ^ Personal communication, 1994, USCG. 



1 Chapter 1 Background and Problem Statement 



