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Galveston District Projects |
Modeling EffortsDiversion Features April 1990 modeling and simulation April 1990 - District commissioned a modeling and simulation study by WES (Bypass Channel) - This investigation was conducted to develop hydrodynamic conditions (water levels and velocities) for use in a tow-simulation study of the influence of the Mouth of Colorado River, Texas, Project on the GIWW. Emphasis was placed upon the proposed intersection of the bypass channel at the GIWW. Technical Report HL-92-11- Hydrodynamics at Mouth of Colorado River, Texas, Project. Numerical modeling of hydrodynamic conditions for Mouth of Colorado to determine water levels, velocities of flow, and wind stress. Results ere verified by actual field measurements during a 25-hour period in may 1990. Two preferred designs of the connecting channel were evaluated with a 27-day dynamic simulation of measured tides for the period 2 through 28 June 1990. A tow simulation was performed using the information generated by the numerical modeling. The simulation involved one, two, and four barge tows at varying cross currents velocities generated by tidal flow. TWOA provided tow operators familiar with the GIWW and the Colorado River intersection. TWOA was satisfied with the simulation. Technical Report CHL 97-6 - Navigation Simulation Study, Mouth of the Colorado River, Matagorda, Texas, March 1997.
The simulation determined that single barge tows were not affected by the crosscurrents. Low tide flows did not have an affect on navigation, only high tidal flows. The flow velocities were isolated and determined that only flows exceeding 1.4 feet per second affected multiple barge tows. Using the numerical model it was determined that flow velocities exceeded 1.4 fps only 15% of the time. Conclusions of the simulation were that only tows of more than one barge would be affected by cross currents exceeding 1.4 fps, which would occur 15% of the time. Recommendations included further study be conducted to design a fender system for the area between the lock and Route 2031 bridge at the junction of the bypass. A physical model was suggested. Monitoring velocity gages should be installed in both the Colorado river upstream of the GIWW intersection and the bypass channel. 1992 Gage installed to monitor currents at bypass channel Physical Model Study 1997-2000 Colorado River Locks Physical Model Study - The purpose of
this study was to identify possible solutions to user concerns for
changed current conditions at the Colorado River Locks and the bypass
channel since completion of the Mouth of Colorado River project. At the
request of the Galveston District, navigation studies were proposed to: b. Examine alternatives for improvement of navigation conditions between the swing bridge, bypass channel, and east lock. The area modeled includes both lock areas and a short portion upstream and downstream from the crossing. The area extended eastward some distance beyond the swing bridge. The physical model was not constructed to evaluate impacts of opening parker's Cut or the proposed southwest cut. The study was initiated in 1997. The base model was completed in March 1998, with alternative testing completed in July 1999. The draft report was completed in October1999. Alternatives modeled were as follows:
Most plans showed very little to modest improvements, removal of the east gates of the west lock showed considerable improvement. Colorado River Southwest Point Corner Stabilization Colorado River Southwest Point Corner Stabilization (Oct 1999- Jan 2000) - WES letter report. The objective of this study is to develop alternatives to prevent erosion of the southwest corner of the intersection of the GIWW and the Colorado River. The protection alternatives must also be suitable for westbound tows to land against if they are unable to cross the Colorado River. This study is not intended to solve the navigation problem which was addressed in the physical model study. Alternatives evaluated as follows:
Recommended alternative is placing dredged material on the southwest point should be considered before any structural alternatives like sandbag dikes or fenders. Comprehensive Study 2001 proposed comprehensive WES study to evaluate the effects of opening the proposed southwest cut, Parker's Cut, a small opening in the diversion dam, or some combination of openings on currents in the GIWW at the bypass channel and the effects the opening will have on salinity, currents, and sedimentation. The study is currently underway with a draft report scheduled for completion in December 2002. Parker's Cut 1995 Request Local Officials of Port of Bay City Authority and Matagorda County request to be allowed to open Parker's Cut. (1995-1996) To pursue consideration of additional access into Matagorda Bay, a meeting was held in October 1995 with local officials. During the meeting it was acknowledged that a model of a new opening would be necessary to determine its impacts on the salinity regime of the bay. A cost proposal was developed for three alternative levels of effort ranging from $218,000 to $608,000. The study costs were to be borne by non-Federal sponsoring entity. No action was taken to implement the studies. LCRA Study September 2000 - Lower Colorado River Authority (Parsons Engineering Science, Inc.) study of Matagorda Bay/Parkers Cut. Jointly funded by LCRA and Matagorda Bay Foundation. This study report was dated 12 September, 2000. The study consisted of modifying the LCRA TxBLEND model of Matagorda Bay to investigate the potential effects of re-opening Parker's Cut on the salinity regime of West Matagorda Bay. Parsons was contracted to perform the model revisions and simulate the re-opening of Parker's Cut wit both the target and critical flows runs from the original Matagorda Bay model. The model was originally developed in 1997. A 4 -foot deep channel was assumed through the cut. The model was run for two conditions, one, the water level the LCRA would like to provide, two, drought conditions. LCRA stated that a more comprehensive model would probably be needed for further consideration. Southwest Cut (1995 - 1996) Hydraulic feasibility of Proposed Southwest Cut, East Matagorda Bay, Texas - This study was commissioned by the Texas Department of Transportation at the request of County of Matagorda, Texas. The objective was to determine the hydraulic feasibility of a proposed water exchange cut in the southwest corner of East Matagorda Bay that would connect the bay to the Gulf of Mexico via the Colorado River Navigation channel. This study was authorized under joint sponsorship of TXDOT and the Texas Parks and Wildlife Department. Field monitoring and hydrodynamic modeling were conducted to assess the hydraulic feasibility of the southwest cut proposed to be opened in East Matagorda Bay, Texas, for increasing water exchange. The overall objective of the study was to determine if a clear reason exists based on the physical processes that might preclude construction of the cut. Sustained monitoring was conducted over a period of three months (Oct 95, to Jan 96) and included synchronized measurements of the water level and current at the eastern and western ends of the bay, wind measurement at the eastern end of the bay, and salinity and other common water-quality parameters at four location in the bay. A depth -integrated numerical simulation model consisting of 8,000 active cells was applied to compute the water level change and horizontal current velocity in East Matagorda Bay, the Gulf Intracoastal Waterway, Mitchell's Cut, the southern end of Caney Creek, the Colorado River Navigation channel, and the proposed southwest cut. The model included wind forcing and Gulf tidal forcing, and calibration was accomplished for a month-long period using measured water level at the eastern and western ends of the bay and at a gauge in the navigation channel, as well as the current measures at both ends of the bay. The following is a summary of conclusions and recommendations
obtained in this assessment: 2. Scour in the wetland area adjacent to the channel of the cut is not expected to occur. 3. Opening of the cut the navigation channel will create only a small cross current in the channel if the design dimensions of he curt are maintained. 4. The cut will decrease the peak flow speed and discharge at the
intersection of the GIWW ad the navigation channel by 25 percent. The
decrease will be greater if the cut scours beyond its design dimensions. Weir Jetty/ Diversion Monitor Completed Projects (1990-1994) Report published in January 1998. The Monitoring Completed Coastal Projects (MCCP) program was established in 1981 by Headquarters, USACE to evaluate the performance of the Corps in planning, design, construction, and operation and maintenance of selected civil works coastal projects. The Colorado River project was nominated for inclusion in the MCCP by the Galveston District in 1984. It was approved for monitoring in FY90 because it met both genetic and site-specific selection criteria. The monitoring effort was conducted by CERC and private contractors in cooperation with Galveston District. The main objectives of the MCCP Monitoring program at the Colorado River project were as follows:
Conclusions reached that the principal management problem is caused by the inadequate size of the impoundment basin and its inefficiency in retaining sediments. Possible alternatives are, to enlarge the basin, extend the basin landward, or deepen the basin. Possible long term solution is possible redesign of the jetties. 1990-1992 - Contract Report CERC-95-3- Longshore Suspended Sediment Transport at the Mouth of the Colorado River, Matagorda, Texas - This contract report was prepared in partial fulfillment of contract with WES. Data was collected in 19990-1992 and was referenced in the WES monitoring report. 2001 - proposed WES study of weir jetty and deposition basin (Operations) Operations contracted with WES as phase two of their studies to
evaluate processes at weir jetty and deposition basin to assist in
formulating alternatives for reducing frequency and volume of dredging
at the mouth of the Colorado River. This work has been completed and a
contract for construction of a training levee in the deposition basin
area is scheduled for advertisement in the last quarter of 2002. Parker's Cut Modeling TWOA Chronicle of events WES LCRA TPWL
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