RGDSS_SurfaceWater_ScopeOfWork

• Title: RGDSS Surface Water Scope of Work
• Description: The objectives of this scope of work are as follows: 1)‎ To apply and enhance an existing data centered surface water modeling system to the San Luis Valley that interacts with the State's central database ‎(HydroBase)‎ and other RGDSS planning tools. 2)‎ To calibrate and test, via application, a San Luis Valley Surface Water Model that, is 100% data centered. 3)‎ To coordinate and share the surface water investigations with SLV water users, the State, a technical subcommittee and other RGDSS contractors.
• Decision Support - Doc Type: Scope of Work
• Date: 11/8/1998
• DSS Category: Surface Water
• DSS: Rio Grande
• Basin: Rio Grande
• Contract/PO #: C153863
• Grant Type: Non-Reimbursable
• Bill Number: HB98-1189, SB99-173
• Prepared By: Leonard Rice Engineering

• It will consist of an application of StateMod, a modeling system developed by the State
during the Colorado River Decision Support System project, to the Rio Grande Basin.
• It will operate on both a daily and monthly time step.
• It will represent all the major streams and tributaries of the Rio Grande Basin from the
headwaters to the state line. This includes creeks that do not contribute to the mainstem,
such as Saguache Creek, and streams that only flow to the Rio Grande under high flow
conditions, such as the Alamosa and La Jara Rivers.
• It will represent 100% of the consumptive use associated with irrigated agriculture,
industrial use, and municipal use in the valley. The surface water diversion structures
that account for approximately 75 percent of the water use in the basin will be modeled
explicitly. The remaining surface water diversion structures will be aggregated into
approximately 25 groups based on location and size.
• It will be 100% data centered using the State's central database, HydroBase, and Data
Management Interfaces (DMI's) consistent with current applications by the State on the
Colorado River.
• It will include the impact of well pumping from different aquifers by including unit
response functions generated by the RGDSS ground water model. Note that this scope
recognizes the limitations of not having a fully linked ground and surface water model in
a basin as complex as the Rio Grande. Task 6.3 addresses many of these concerns. In
addition, the State, under a separate joint funding agreement with the USGS, is in the
process of performing a preliminary assessment of the effort required to cooperatively
develop a fully linked surface and ground water model. However, based on the
feasibility study recommendation, afully linked surface and ground water model is not
currently envisioned for development as part of RGDSS.
• Enhancements to the StateMod modeling system required for the Rio Grande Basin that
will be performed by the State include: 1) refining the system efficiency component, 2)
adding a ground water component; and 3) adding a futile call component. Other
enhancements to the StateMod system may also be made by the State as determined
necessary over the course of the project.
1. System Efficiency is used in the current StateMod as a lumped parameter. It may be
refined by the State to be represented by conveyance loss and on-farm loss
components in order to be consistent with the approach used by the Water Budget and
Consumptive Use tasks. In addition, consideration will be given to accounting of soil
moisture storage.
2. Ground Water is currently simulated in StateMod to estimate the lagged return to
the stream of unused diversions. It will be refined by the State to allow
representation of the lagged effects of ground water pumping on the stream.
RGDSS Surface Water Scope of Work 4 11/8/98