Arroyo Colorado

Enhancing Water Quality and Dredged Material for the Port of Harlingen (Phase I)

Project Overview

Funding Source

Funding provided by General Land Office as part of the Costal Management Program.

Project Description

Maintaining and protecting the water quality of the Lower Laguna Madre, an important nursery for fish, shrimp and crab and a popular site for recreational fishing and boating, is imperative for the health of the Texas coast. However, the low dissolved oxygen (DO) concentrations in the Arroyo Colorado, the primary source of freshwater for the Lower Laguna Madre, have killed millions of fish over the past few decades. Most of these fish kills occurred in the tidal segment of the Arroyo, which directly flows into the Lower Laguna Madre. To address the DO impairment, the Arroyo Colorado Watershed Partnership (Partnership) developed the Arroyo Colorado Watershed Protection Plan (WPP), a comprehensive watershed-based strategy to improve water quality and aquatic and riparian habitat in the Arroyo Colorado. One of the top strategies for water quality improvement identified in the WPP is the construction of wetlands for removal of nutrients. Therefore, the Port of Harlingen and the Texas Water Resources Institute (TWRI) will construct a wetland to remove nutrients from spoils dredged from the turning basin at the Port of Harlingen, Texas.

The Port of Harlingen is located in the heart of the impaired tidal segment of the Arroyo Colorado, which is classified by the Texas Commission on Environmental Quality as the segment between the confluence with Laguna Madre in Cameron/Willacy County to a point 100 meters (110 yards) downstream of Cemetery Road in Cameron County. This part of the water body is also defined as a coastal natural resource area (CNRA) and a coastal wetland in the Coastal Coordination Act. The location of the wetland is on an approximately 35 acre site where dredge spoils from the turning basin were previously dumped downstream of the Port of Harlingen on the northwestern bank of the Arroyo Colorado. By impacting this key location within the Arroyo Colorado, the resulting water quality improvements will positively affect the water quality within the Lower Laguna Madre maintaining its health as a vital coastal nursery and ecological and economic resource.

Funding will address two major funding categories and goals within the Coastal Management Program: water quality and quantity improvements and enhancement of critical areas. Water quality issues associated with the Arroyo Colorado and the Lower Laguna Madre will be addressed through the construction of an approximate 35-acre wetland that will be designed and built to protect critical habitat and provide nutrient removal from dredge spoils from the turning basin from the Port of Harlingen. The spoils contain nutrients from two sources: 1) nonpoint source pollution during Port activities (loading, unloading, stormwater runoff) and 2) detachment from upstream sediment that settles out of the water column in the turning basin (a wider, deeper segment of the stream that has slower flow). By removing these nutrients, the spoils can be purchased and used as beneficial amendments in other areas of the watershed, which will provide revenue for sustaining the sediment basin and wetland system. In addition to improving water quality

Project Tasks

Task 1: Texas A&M AgriLife, TWRI will effectively coordinate and monitor all technical and financial activities performed under this contract, prepare progress reports, and maintain project files and data. TWRI will be responsible for hiring and supervision of all project personnel.

Task 1 Deliverable and Timeline.

  1. Project Oversight - TWRI will provide technical and fiscal oversight to ensure Tasks and Deliverables are acceptable and completed as scheduled and within budget.
  2. Fiscal/invoicing - Texas AgriLife Research will submit reimbursement forms per the schedule established/requested by the GLO.
  3. Regular Meetings - To facilitate good communication between project participants, a quarterly meeting or teleconference will be scheduled and hosted by TWRI.
  4. Quarterly progress reports - TWRI, with the assistance of the Arroyo Colorado Watershed Coordinator (ACWC), will submit progress reports to GLO quarterly. The reports will include the status of deliverables for each Task and a narrative description of activities for each task outlined in this Scope of Work in Progress Report format.
  5. Final Report - TWRI, with assistance of the ACWC, will provide GLO with a comprehensive report on the activities during the course of this project. March 2011.

Task 2: An ecological assessment will be conducted to determine appropriate locations for wetland/sediment basins. Efforts will be made to preserve natural habitat where possible and incorporate natural components of the landscape. Therefore, plants will be identified and mapped in order to ensure that native, threatened, and endangered plants are preserved on the site and incorporated into the design. The assessment will also delineate wetlands on the property and identify areas that are prone to erosion and thus should be avoided during construction.

Task 2 Deliverable and Timeline.

  1. A coordination meeting with Port of Harlingen staff, Alan Plummer Associates, Inc (APAI)., TWRI, and University of Texas at Brownsville (UTB) faculty (to be conducted by conference call) will be held to discuss goals and objectives of studies to be conducted.
  2. Ecological Assessment - The UTB will identify native and non-native flora and fauna, delineate wetland areas, determine soil types and erosion concerns on the approximately 35 acre site located on the northwestern bank of Arroyo Colorado at the Port of Harlingen, Texas.
  3. Report and map - The UTB will provide a final report and GIS map to APAI and the GLO that includes species identified and highlights which areas should be avoided and which should be incorporated into the design of the sedimentation basins and treatment wetlands. January 2010
  4. Permit Requirement Coordination - After review of reports prepared by UTB documenting ecological studies, APAI will coordinate with state and federal agencies regarding determination of new permits required for construction of a system of sedimentation basins and wetlands to polish decant water from the dredging operations as well as associated amenities including conveyance of outflows back to the Arroyo Colorado. It is anticipated that coordination with U.S. Army Corps of Engineers' Operations Division, Engineering Division, as well as Regulatory Branch may require an on-site meeting with the representatives as well as representatives from the coordinating review agencies including the GLO, Texas Parks and Wildlife Department, U.S. Fish and Wildlife Service, U.S. Environmental Protection Agency, Texas Commission on Environmental Quality, and potentially others. March 2011

Task 3: Alan Plummer Associates, Inc. (APAI) in cooperation with the Port of Harlingen will analyze the following data for the proposed project site as part of the technical review and analysis. APAI will be responsible for gathering listed data:

  1. Hydrological data
  2. Soils data
  3. Previous geotechnical report(s), if any, for the proposed project area
  4. Available topographic data
  5. Environmental and/or ecological reports for the proposed wetland site

Task 3 Deliverable and Timeline.

  1. A coordination meeting with Port of Harlingen Staff, APAI, and TWRI will be held to discuss goals and objectives of analysis to be conducted (via conference call).
  2. Survey - The Port of Harlingen will have the 35 acre site surveyed, with guidance from APAI, on the criteria for the survey (density of shots, format, etc.). January 2010
  3. Conceptual layout of the wetland - Once the surveying services have been completed, APAI will review the survey and other data provided by the Port of Harlingen and UTB, and will develop a conceptual layout of the wetland/sediment basin. APAI will provide three copies of a draft conceptual plan to the Port of Harlingen Staff and project team partners to review approximately one week in advance of a meeting to discuss and finalize the conceptual design of the wetland/sediment basin. APAI will then travel to the site and meet with Port of Harlingen staff and project team partners on site for project team partners to verify the selected site on the ground. August 2010
  4. Conceptual Design Report - APAI will prepare a Draft Conceptual Design Report documenting conceptual layout of the Project and the data gathered in Subtask 3.1. APAI will provide three copies of the draft Conceptual Design Report to the Port of Harlingen and project team partners for comment. APAI will finalize the Conceptual Design Report based on comments received. The Conceptual Design Report will be used in future Project phases (securing permits, etc.). December 2010
Project Personnel
Allen Berthold
Project Manager, TWRI
Dr. Elizabeth Heise
Assistant Professor, University of Texas at Brownsville
W.G. "Butch" Palmer, Jr.
Port Director
Loretta E. Mokry
Associate, Alan Plumber Associates, Inc.
Allen Berthold
Project Manager, TWRI