Watershed Protection Plan - Lower Rio Grande Valley Development ...

ELEMENTS OF THE ARROYO COLORADO WATERSHED PROTECTION PLAN
Prior to 2006, the standard operating procedures
used for shipping by Rio Grande Valley Sugar
Growers, Inc., the leading sugar processing company
in the Arroyo Colorado watershed, included dumping
truckloads of raw sugar onto the loading platforms
at the Port of Harlingen and using front-end loaders
(i.e., bulldozers) to load the sugar from the platforms
onto barges for shipment north through the GIWW. At
the end of each sugar loading operation, the loading
platforms were sprayed with large fi re hoses and the
excess sugar remaining on the platforms was washed
directly into the Arroyo Colorado, increasing the loading
of BOD into this portion of the stream.
will continue to cause low DO in the Arroyo Colorado
periodically despite improvement in water quality. The
ACW Partnership has participated in discussions
with individual stakeholders regarding artifi cial
enhancement of aeration in the Zone of Impairment
of the Arroyo Colorado using mechanical aerators or
other engineering or structural controls. However,
not much site-specifi c research has been conducted
to date to assess the feasibility of these types of
controls. Engineering controls for enhancing DO in the
Arroyo Colorado remain an option for consideration in
subsequent phases of the ACW Protection Plan.
Top Strategies for Water
Quality Improvement
The ACW Partnership prioritized the strategies for
improving water quality in the Arroyo Colorado identifi ed
by the partnership’s Work Groups and developed the
following list of the top 10 water quality improvement
strategies to guide implementation of the ACW
Protection Plan:
Loading raw sugar for shipment north
Beginning in 2006, Rio Grande Valley Sugar
Growers, Inc., began testing an alternative method for
removing excess raw sugar remaining on the loading
platforms at the end of loading operations. The method
involves using a street sweeper to collect and dispose
of the excess raw sugar left on the loading platforms.
Rio Grande Valley Sugar Growers, Inc., is currently
evaluating the effectiveness of this and other methods
of preventing the loading of excess raw sugar into the
Arroyo Colorado. This includes plans for construction
of a new loading facility located in an area adjacent
to the Port of Harlingen. The new facility will use the
most current loading and storage technology designed
to prevent loss of raw product to the environment. The
new facility is scheduled to be built between the years
2010 and 2015.
The ACW Partnership recognizes that the
occurrence of low DO in the upper portion of the Arroyo
Colorado Tidal is due, at least in part, to hydraulic
effects that occur in the dredged navigation channel
under certain conditions. It is unclear if these effects
• Construction of individual wetlands and pond
systems for removal of nutrients from treated
wastewater
• Construction of regional wetland systems for
removal of nutrients from multiple sources
• Implementation of WQMPs and RMSs on
agricultural land in the watershed
• Improvement of wastewater infrastructure
• Conservation and restoration of existing riparian
and wetland habitats
• Stabilization of fl oodplain and stream to reduce
bank erosion and improve riparian and aquatic
environments
• Elimination of data gaps and implementation
of additional water quality monitoring to aid in
decision-making and to enhance E&O
• Promotion and evaluation of urban BMPs that
focus on water quality improvements
• Enhancement of efforts to inform and engage
stakeholders and the public
• Creation of a geographical information system
(GIS) to manage data in ways that support
adaptive management
Arroyo Colorado Watershed Protection Plan 88 January 2007