Great Lakes Basin Pilot

Surface-Water Flows and Storage

The major tasks include:

• Development of techniques to estimate flow in ungaged basins,
• Development of techniques to deliver real-time estimates of surface-water flows for the U.S. side of the Great Lakes Basin,
• Analysis of trends in streamflow and precipitation using data collected over the past 90 years (see Historical Changes in Precipitation and Streamflow in the U. S. Great Lakes Basin, 1915-2004),
• Exposition of the changes in Great Lake water levels over the past 4500 years and the relation to water availability (see Lake-Level Variability and Water Availability in the Great Lakes).

Status

A prototype model, aFINCH (analysis of Flows in Networks of Channels), has been developed and applied to a hydrologic subregion within the U.S. Great Lakes Basin (0405).

The model provides an estimator of flows in reaches and runoff from catchments in the NHDPlus network. Features of the estimator include:

• Consistent with monthly flows measured at USGS streamflow gaging stations;
• Account for water withdrawals, diversions, and augmentations;
• Robust estimates of flows and runoff at ungaged sites that are consistent with environmental factors affecting measured natural flows, which are gaged flows adjusted for water use;
• Conserve mass through the network;
• Support near real-time estimation;
• Provide extensive graphical support for input and output;
• Nonproprietary, open-source code that can be made portable across the USGS network.

A schematic of the design of aFINCH and example results from the application of this model for October, 2003.

Constrained run-off for October, 2003 from aFINCH analysis for hydrologic subregion 0405.

Accumulated flow in NHDplus stream network for hydrologic subregion 0405 for October, 2003 estimated using aFINCH constrained regression.