Upper Mississippi River System Integrated Water Availability Assessment
Research Team Members
Objective:
The overall objective of the research is to characterize the river flow in the navigable channels of the Upper Mississippi River Basin to determine probable risks of having insufficient conditions (too low flows or too high flows) for navigation in the channel network, determine the sensitivity of these risks to possible future additional water withdrawals or inter-basin water transfers, and develop policies among the five states signatory to the Upper Mississippi Riber Basin Association for managing water uses in the UMRB. Specifically, the five objectives are: 1) Estimate the existing hydrologic flows from the basin watersheds into the Upper Mississippi River System navigation channel, 2) Assess how diversions and consumptive uses affect the hydrologic flows from the basin watersheds into the UMRS navigation channel, 3) Determine the thresholds of discharge in various reaches at which negative impacts may occur to the UMRS navigation channel (including duration and frequency of occurrence), 4) Scope follow-on research goals for assessing the implications of limited water availability analysis for river products and services beyond the UMRS navigation channel – e.g., impacts to drinking water, recreation, and aquatic ecosystem health of the UMRS, 5) Convene interstate conversations among Illinois, Iowa, Minnesota, Missouri, and Wisconsin technical experts and agency leaders to a) learn the research findings, b) relate the research findings to management and policy decision making and c) recommend principles and policies for cooperative and effectively managing the water resources of the Upper Mississippi River basin.
Approach:
The immediate task is to determine the risk to navigation in the channels of the UMRB. This task will be achieved by acquiring streamflow data from gauging stations at the mouths of the fourteen HUC-6 watersheds within the UMRB, and other gauging station sites along the navigable channel network. These streamflow records will be subjected to analysis using the USGS’s SWToolbox software to derive low-flow and high-flow frequency characteristics for each gauging station. These flow statistics will be used to evaluate the risk of the different sections of navigable channels not meeting flow-condition navigation standards.
The flow characteristics derived in the first task are for historical conditions, but there is a need to know the effect of changes in water allocations within the basin on those flow characteristics. For the second research task the effect of changes in water allocations will be evaluated using hydrologic model simulations to evaluate the sensitivity of channel low-flow and high-flow statistics to potential scenarios of changes in water allocations.
Throughout the process of hydrologic analysis the research team will work closely with state representatives from the UMRBA to seek information and guidance related to current water resource allocations, and proposed future allocations. The research team will work with the state representatives to develop policies and procedures for evaluating proposals on water allocations.
Impact:
The project will provide guidance to the UMRBA for ways to manage water uses within the UMRB. It is expected that this project will also serve as a format for other basins to conduct similar studies.Abstract:
As with any river system on the earth, the flows in the channel network of the Upper Mississippi River Basin are determined by the precipitation, the evaporation potential, the types of soils and landuses, the properties of the aquifer system, and the water withdrawals made for commerce and daily human needs. Variable weather patterns are a primary cause for the variability of flows in river systems, but then on top of that human imposed changes in landuse and direct withdrawals of water from surface waters or groundwater will have long-term impacts on the river flows.
Water resource managers involved in making decisions about water allocations need to comprehend the impact that changes in allocations will have on river flows. Changes in allocations might come in the form of increased land area for row crop production, or increased water withdrawals to provide cooling water for energy production or for data centers.
As a first step in this project the historical flow data for gauging stations within the UMRB will be utilized to characterize the river flows in probabilistic terms, and this derived information will be used to quantify the risks associated with river flows meeting the needs of navigation within the basin river network. A second step will then build upon those initial results to assess the impact of potential changes in water allocations on the ability of the river system to meet those needs.
A key component of this project is to work closely with the representatives from the five member states that compose the Upper Mississippi River Basin Association. Those representatives are key to providing information about current water resource allocations in their respective states. The collaborative effort with the states is also key to development of policies for how best to determine future water allocations.
In the longer term it is important to quantify the effect of human imposed changes (landuse change or direct water withdrawals) in watersheds on other important water related features in river systems, including recreation, water quality, and ecosystem functioning. To address this issue this project will develop a plan for a follow-up study on how river flow variability and human water use potentially could affect the well-being of the river systems.