BASELINE AND CONSTRUCTION MONITORING OF PACKERY CHANNEL, CORPUS CHRISTI, TEXAS Deidre D. Williams1, Nicholas C. Kraus2, F. J. Kelly3, Andrew N. Smith4, and Carl M. Anderson5 Abstract: Construction of a new inlet along the Texas Gulf Coast to Corpus Christi Bay, Texas, began October 2003. In preparation for the inlet opening, in August 2003 the U.S. Army Corps of Engineers, Galveston District, initiated baseline and construction monitoring of the existing Packery Channel and adjacent Padre and Mustang Island beaches. The monitoring program, contracted to Texas A&M University-Corpus Christi, includes beach profile surveys, shoreline position surveys, hydrographic surveys, acquisition of aerial photography, current measurement in the existing channel, and data dissemination through a web site called Texas Inlets Online. This paper discusses objectives of the monitoring, elements of the monitoring plan, and selected results. INTRODUCTION Historically, Corpus Christi Bay, Texas, was served by two natural inlets (Price 1952) or “passes” in local terminology, Aransas Pass (shared with Aransas Bay to the north) on the north side and Corpus Christi Pass on the south side, in the SSW corner (Fig. 1 and Fig. 2). Dredging of Aransas Pass started in 1924, and its re-direction into Corpus Christi Bay caused Corpus Christi Pass to slowly shoal and become a flat ephemeral overwash pass that can be flooded during more severe tropical storms and hurricanes. For many years, local interests have wanted to reopen the old Corpus Christi Pass through an existing dead-end channel called Packery Channel for water exchange (environmental enhancement for southern Corpus Christi Bay and upper Laguna Madre) and as a navigational amenity that would allow access to the Gulf of Mexico without having to make a 23-mile additional transit to reach Aransas Pass. In addition, such a new pass would serve as a harbor of refuge for vessels to the south in the Gulf of Mexico. The North Padre Island (Packery Channel), Nueces County, Texas, Storm Damage Reduction and Environmental Restoration Project was authorized in the Water Resources Development Act (WRDA) 1999 as a Federal project with Nueces County as the original local sponsor. The City of Corpus Christi assumed local sponsorship in 2000. Construction began in October 2003, and the inlet opening is expected in spring or 1) The Conrad Blucher Institute for Surveying and Science (CBI), Texas A&M University-Corpus Christi (TAMU-CC), 6300 Ocean Drive, Corpus Christi TX 78412. [email protected]. 2) U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, 3909 Halls Ferry Rd., Vicksburg, MS 39180. [email protected]. 3) CBI, TAMU-CC, [email protected]. 4) U.S. Army Engineer District, Galveston, Southern Area Office, 1920 N. Chaparral, Corpus Christi, TX 78401. [email protected]. 5) U.S. Army Engineer District, Galveston, 2000 Fort Point Rd., Galveston, TX 77550. [email protected]. summer 2005. The inlet will be stabilized by two parallel jetties spaced 300 ft apart extending 1,430 ft into the Gulf of Mexico from the existing shoreline, protecting a channel to be maintained to a depth of 14 ft Mean Lower Low Water (MLLW), with provision for advanced dredging and overdredging of 2 ft. Sand dredged from the channel as new work and maintenance material will be placed on adjacent beaches as a shore-protection element (USACE 2003). The U.S. Army Corps of Engineers (USACE) recognizes that inlets can alter the adjacent beaches by redistributing sediment. A physical-processes monitoring program and environmental-processes program were implemented to provide baseline data to understand the existing condition and response of the beaches, nearshore, and channel for guiding dredging and dredged material placement practice. In addition, design studies (Kraus and Heilman 1997; Brown and Militello 1997; URS/Dames & Moore 2001) for the project indicated that Packery Channel is located near a divergent nodal point in longshore sediment transport. Monitoring is essential for understanding the acting physical processes as well as for adaptive management of the inlet and adjacent beaches as a sediment-sharing system. This paper discusses the physical processes monitoring plan and selected results, including availability and location of data for interested parties. Houston Port Arthur LA United States Galveston Bay Galveston Texas Island Map Area Matagorda Mexico Bay Lavaca Bay Port O’Conner Corpus Christi Bay Corpus Aransas Pass Christi Baffin Packery Channel Bay Gulf Padre Island National Seashore of Mexico South Scale Padre Island 10 0 10 20 Brownsville Statute Miles 20 0 20 40 Mexico Kilometer Mouth of Rio Grande Figure 1. Location of Packery Channel, Corpus Christi, Texas. MONITORING PROGRAM DESIGN A baseline and construction monitoring program of nearshore morphology, sediment grain size, channel bathymetry and current at Packery Channel and adjacent beaches was initiated by the U.S. Army Engineer District, Galveston, in August 2003. The study concerns the existing channel and adjacent beach on North Padre Island located along the 2 central Texas coast at Corpus Christi (Fig. 1, Fig. 2). The Galveston District initiated this effort in conjunction with the U.S. Army Engineer Research and Development Center (ERDC), Coastal Inlets Research Program (CIRP), which contracted to the Conrad Blucher Institute for Surveying and Science (CBI) at Texas A&M University-Corpus Christi for the field data collection and data dissemination. The 3-year monitoring program began in anticipation of the commencement of scheduled September 2003 construction activities. Presently, the channel begins at the Gulf Intracoastal Waterway (GIWW) and extends southeast toward the Gulf of Mexico, where it terminates within Padre Island. For additional historic information on Packery Channel including research and design the reader is directed to a companion conference paper (Kraus et al. 2005). Figure 2. Study area and beach profile locations, Padre and Mustang Island beaches. Kraus and Heilman (1997), URS/Dames & Moore (2001), and Kraus et al. (2005) describe the initial data collection and analytical studies leading to functional design of Packery Channel Inlet. Beach profile surveys and sediment samples were taken during the course of the initial study and are available for comparison to present study data. Mobilization and construction began during October 2003, with 55% of the project completed as of December 2004. Table 1 summarizes the timeline of construction 3 progress and anticipated progress over the course of the 2005 fiscal year. The project is on schedule with a completion date of August 2005. Table 1. Packery Channel Construction Timeline Task Description Initiated/Issued Completed Comment Contract Award July 31, 2003 -- -- Notice to Proceed August, 22 2003 -- -- Construction Starts October 2003 -- -- Construct Permanent Fill October 2003 January 2005 -- Construct Shoreline Protection September 2004 December 2004 -- Construct Jetties August 2004 -- -- Dredge Reach 1/Bypass Sand January 2005 -- -- Dredge Reach 2 December 2003 April 2004 110,000 cy removed Install Sand-Bypass/Utility Casing January 2004 January 2004 -- Contract Completion Date -- August 2005 Anticipated Monitoring Tasks The monitoring effort is to provide a dynamic local network of research and technical support to compliment Galveston District and CIRP initiatives for monitoring existing inlets and the response of the coast to development of new inlet infrastructure. The project encompasses data collection and analysis in support of present and continuing studies of Packery Channel and other existing and proposed inlets along the Texas coast either managed or permitted through regulatory authority by the Galveston District. Increased understanding of the hydrodynamics and sediment transport of these inlet systems will assist in improving inlet design and channel maintenance, thereby optimizing operation and maintenance benefits. The purpose of the 3-year Packery Channel monitoring project is to document baseline conditions as well as changes during and immediately after construction for both the existing channel and along the Gulf of Mexico beaches of Padre and Mustang Island. The monitoring program includes the following tasks: Task 1. Geographic Information System for Central Texas Inlets Analysis Develop/operate web-based data dissemination center Develop baseline Arc GIS Packery Channel Inlet Project Obtain aerial photography Task 2. Inlet and Channel Morphology Surveys Conduct beach profile surveys Conduct channel hydrographic surveys Conduct shoreline position surveys Task 3. Current Monitoring Install/maintain current monitoring station in Packery Channel at GIWW intersection. Establish/maintain real-time link to CBI database and web site 4 Texas Inlets Online, Task 1 The Texas coast contains 24 natural and engineered inlets (exact number depending on storms) providing for water exchange and navigation between the Gulf of Mexico and the inland bays and lagunal systems. In particular, it is served by eight federally maintained ship channels together with a number of natural inlets and river mouths of interest to the Galveston District. The data collected at Packery Channel was arranged in a webpage1, shown in Figure 3, that serves as a prototype for development of online data archives for other inlets along the Texas coast. Figure 3. Packery Channel web-based data dissemination