summary of streamflow conditions and usgs low-flow activities
DESCRIPTION
Summary of Streamflow Conditions and USGS Low-Flow Activities. State Drought Task Force Meeting March 29, 2012 St Paul, MN - Webinar. James Fallon, Dave Lorenz, Greg Mitton USGS, Mounds View, MN [email protected] 763-783-3255. U.S. Department of the Interior - PowerPoint PPT PresentationTRANSCRIPT
Summary of Streamflow Conditions and USGS Low-Flow Activities
State Drought Task Force MeetingState Drought Task Force MeetingMarch 29, 2012March 29, 2012
St Paul, MN - WebinarSt Paul, MN - Webinar
U.S. Department of the InteriorU.S. Geological Survey
James Fallon, Dave Lorenz, Greg MittonUSGS, Mounds View, MN
[email protected] 763-783-3255
Photo of dry channel at Minnesota River at Montevideo, 1932
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TopicsTopics• Summary of Streamflow ConditionsSummary of Streamflow Conditions• Mississippi Low-Flow Report FindingsMississippi Low-Flow Report Findings• Low-Flow Statistics & Web ResourcesLow-Flow Statistics & Web Resources• Low-Flow Triggered ActivitiesLow-Flow Triggered Activities
– Extra low-flow measurementsExtra low-flow measurements– Mississippi River GW Seepage Study between St Cloud and Elk RiverMississippi River GW Seepage Study between St Cloud and Elk River
Le Sueur River near RapidanSept. 28, 2011 31 cfs
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Summary of Streamflow Summary of Streamflow ConditionsConditions
1.1. Background: snowmelt peaks are often greatest flows of year for northern 2/3’s of MinnesotaBackground: snowmelt peaks are often greatest flows of year for northern 2/3’s of Minnesota
2.2. Most streams have peaked due to snowmeltMost streams have peaked due to snowmelt
3.3. Peaks are about 1-month earlier than usualPeaks are about 1-month earlier than usual
4.4. Most peaks are smaller than normal Most peaks are smaller than normal Typically about 25Typically about 25thth percentile percentile
Some flows extremely low but masked from seasonSome flows extremely low but masked from season
5.5. Spring rains could change all thisSpring rains could change all this
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OverviewOverviewMuch of US experiencing below-normal Much of US experiencing below-normal streamflowstreamflow
Northern US gages not reporting: ice-affected
http://waterwatch.usgs.gov/new/index.php?id=dryw http://waterdata.usgs.gov/usa/nwis/rt
Minnesota Flow Conditions Minnesota Flow Conditions SimilarSimilar
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First glance: flows seem normalwith low flows in south & NE
Look closer at hydrographs with respect to season and timing
http://waterdata.usgs.gov/mn/nwis/current/?type=intro
7Pigeon
Flow-Duration Hydrographs Flow-Duration Hydrographs from Selected Streamgages from Selected Streamgages
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7Buffalo
7DesMoines
5Kawishiwi
7Prairie
Red-Fargo 8
Basswood8
7Miss-B
Crow8 7Miss-AnokaMN-Monte8
7MN-Jordan
71. Snake current
7StraightLeSueur8
WaterWatch Duration Hydrographs http://waterwatch.usgs.gov/new/index.phpCurrent Streamflow Conditions http://waterdata.usgs.gov/mn/nwis/current/?type=flow
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Mississippi River Low Flow Mississippi River Low Flow ReportReport
“Normal” snowmelt runoff peak at Le Sueur River near Rapidan, March 23, 2007. Measured 3,260 cfs after peak (trees on left bank).
So what do these low-flow conditions look like?
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Mississippi River Low Flow Mississippi River Low Flow ReportReport
Same view of channel last fall.September 28, 2011. 33 cfs
Cobble Riffle
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Flow this spring: March 7, 2012. Just past snowmelt runoff peak. Peak was <1,000 cfs (about 1.5 ft higher than shown in picture). View looking upstream of same cobble riffle.
Low-Flow Characteristics Low-Flow Characteristics of the Mississippi Riverof the Mississippi River
Dave Lorenz and Erich KesslerUSGS Minnesota Water Science Center
Research supported by the Met Council (2008)
http://pubs.usgs.gov/sir/2010/5163/
Study Objective and Study Objective and ApproachesApproaches
Characterize the regional low flows in the Mississippi River upstream of Minneapolis.
Part 1. Review low-flow duration statistics for the Miss. R. near Anoka, one upstream site (Grand Rapids), and three tributaries (Crow R., Crow Wing R., and Rum R.) as well as the headwaters reservoirs.
Part 2. Construct a very large sample of potential flows, by superpositioning observed summer flows on observed snowmelt flows.
Implications, Part 1Implications, Part 11. The greatest threat from low flows occurs when the
Mississippi River near Anoka and the upstream basins experience low flows.
2. The assumption that droughts and corresponding low flows are widespread is not necessarily true. There are several instances of low flows in one or two basins and not in the other basins.
3. In general, the headwaters reservoirs are at or below their summer operating range during lowest flows in the Mississippi River.
Approach, Part 2Approach, Part 2
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
5000
10000
15000
20000
25000
30000
Flow.1976Flow.2003Synthetic Flow
Implications, Part 2Implications, Part 2The greatest threat from the lowest flows occurs before the end of June when a dry spring follows a snowmelt peak of less than 11,300 cubic feet per second.
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Low-Flow Triggered Low-Flow Triggered ActivitiesActivities
1.1. Discharge Discharge measurements measurements at low-flow sitesat low-flow sites
2.2. Mississippi River Mississippi River Groundwater Groundwater Seepage Seepage Synoptic Synoptic MeasurementsMeasurements
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Additional Drought Additional Drought ResourcesResources
http://mn.water.usgs.gov/infodata/lowflow/
Low-Flow Statistics Web PageDrought-related Web Page
http://mn.water.usgs.gov/drought/
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Questions?Questions?1.1. Snowmelt peaks are often greatest flows of year for northern 2/3’s of MinnesotaSnowmelt peaks are often greatest flows of year for northern 2/3’s of Minnesota
2.2. Most streams have peaked due to snowmeltMost streams have peaked due to snowmelt
3.3. Peaks are about 1-month earlier than usualPeaks are about 1-month earlier than usual
4.4. Most peaks are smaller than normal Most peaks are smaller than normal Typically about 25Typically about 25thth percentile percentile
Some flows extremely low but masked from seasonSome flows extremely low but masked from season
5.5. Many conditions in Upper Mississippi Basin “right” for severe low flow in MetroMany conditions in Upper Mississippi Basin “right” for severe low flow in Metro
6.6. Spring rains could change all thisSpring rains could change all this