A research tool developed by engineers with the International Rainy Lake Board of Control will be helpful for a variety of uses, including when the rule curves that guide lake level management are reviewed in 2015.
The Rainy River hydrology model is a new mathematical research tool that provides raw data to help develop statistics on water flow, elevation and duration.
The data model pools daily trace water basin measurements to develop hydrological statistics from the eastern basin tributaries near Lake Superior to the westward end at Lake of the Woods.
“This is not a real time reservoir model,” said Ed Eaton, engineering advisor with the IRLBC. “Think of the hydraulic model as a tool, and understand that it does not provide specific answers to everything.”
“It provides a hydraulic relationship that is absolutely essential for any development model with environmental factors,” he added. “From that information we can develop statistics and relationships to habitat models that interface with the environment.”
Eaton said the model was developed by engineers with international watershed boards to expand its water quality function. Also included was air, water, health and environmental factors of Rainy River, Rainy Lake, Namakan Lake and Lake of the Woods.
The geometry can change from year to year, he said. The water elevation and river scour are also impacted by the morphology of the riverbed.
“Flow doesn’t tell the whole story,” said Eaton.
The hydraulic model is an International Joint Commission directive, as part of its International Watersheds Initiative priorities for the 21st century. Eaton said the IJC wants to amalgamate existing boards and resources, and improve trans boundary discourses on mining, hydropower and other basin issues.
The working model has been demonstrated at work group meetings and a final report will be submitted to the IJC by the end of the year. Eaton said the model would be useful in producing data for the normal rule curve assessment review in 2015.
“The commission should have sufficient information on how to conduct its review and what information gaps are important to fill,” said Eaton. “We are not going to collect all that we want to on the environment; but we can know what indicators to look at and which ones are already covered by existing agency programs, which ones lack funding and how to get it to them.”
If funding was not a factor, Eaton said that satellite monitoring gauges for depth, flow and temperature at the several inflow areas all over the basin would give early and detailed data about rainfall and stream inflows, outflows and depth measures.
“It can take weeks to materialize downstream,” he added.
IJC members also want more mapping of river bottoms, banks, levees and other protections.
The monumental task of developing the model with limited resources mean building on what already has been done and then filling in the gaps, said Eaton. The Minnesota Department of Natural Resources, the U.S. Army Corps of Engineers and other agencies have done some mapping and hydrology or habitat monitoring.
The IRLBC conducted 288 cross sectional scans, about three per mile, on 90 miles of Rainy River. It also did acoustic Doppler soundings, a non-intrusive measurement of water flow velocity and frequency.
The flow velocity vector information is good cross-section data for biologists and fisheries models, said Eaton.
“The information was very detailed,” he added.
Planes conducted Federal Emergency Management Agency standard digital contour terrain mapping of the over bank elevation with a wetted perimeter. Optical laser range detecting technology was also used.
The budget allowed for 2,000 foot swath scans from the river center, said Eaton, and he said he would like future efforts to measure out to the 500-year flood plain. The over bank contour data is useful for development and habitat planning along the river, he said.
The data “drives” various hydrological output models for the agencies that will use it for specific needs, he said. It can also be used for reports on water level or habitat, temperatures and spawning.
The data can help industry and governments minimize the impact on spawning, a cycle that starts with temperature changes at key times in the year. The data could also offer use as a sediment model and has capabilities with dissolved oxygen, he added.
Eaton said the model should not be confused with existing visualization models that are designed to output key information for industrial or dam use. Theses programs, he said, are not useful for the total variability needs of the Rainy Lake basin, and require this strictly engineering tool.
The model is a sophisticated mathematical tool with parameters, he added. When data input is outside of those parameters it can run into discontinuities or “friction factors” that won’t converge.
“Then they go back and look at which parameters to adjust,” he said. “Anyone who does modeling deals with this constantly.”
Eaton said agencies and groups often hire engineers to conduct hydrology studies on issues of concern. These engineers could use the data for work with water levels, flow, or habitat models to reveal impact on habitat and spawn mortality.
