Hiawatha Golf Course - Minneapolis Park and Recreation Board...Hiawatha since the 1960s In late...
Transcript of Hiawatha Golf Course - Minneapolis Park and Recreation Board...Hiawatha since the 1960s In late...
UpdateoninvestigationsandPhaseTwoworkplan29November2016
Hiawatha Golf CourseMinneapolis Park & Recreation BoardCity of Minneapolis
Meetingpurpose
There are three primary goals for this meeting:o To briefly review findings from Phase One investigationso To describe Phase Two investigationso To update the public and neighbors on the status of related
investigations and activities
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Distinguishinginputstothelake
o East 43rd Street pipeo Minnehaha Creeko Golf course ponds and
pumps
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PhaseOneprimaryissue
The MPRB has been pumping stormwater and groundwater from ponds on the golf course to Lake Hiawatha since the 1960s
In late 2015, the volume of water pumped from Hiawatha Golf Course was discovered to be far greater than allowed by a Groundwater Appropriation Permit issued by the Minnesota Department of Natural Resources in 1993
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PhaseOneinvestigations
Understanding the amount of water pumped from the golf course required that we:
o Gather existing groundwater data and develop a groundwater model
o Develop a stormwater model to understand non‐groundwater inflows to the ponds
o Understand the interaction of groundwater and stormwater under a variety of high water and flooding scenarios
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PhaseOneinvestigations:pumpedwater
Measured pumped water using flow meterso Flow meters installed in two pumps in November 2015o Allowed for the calculation of a reasonable estimate of
volume of water pumped annuallyo Approximately 263 million gallons of groundwater pumped
annually according to measurements and calculationso Current appropriations permit allows 36.5 million gallons of
groundwater to be pumped
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PhaseOneinvestigations: pumpedwater
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(100 gpm)groundwater
(137 gpm) groundwater
(196 gpm)
(70 gpm)groundwater
Net inflow to pondso 40% of inflow is from Lake
Hiawatha (lake seepage)o 60% of inflow is regional
groundwatero 263 million gallons of
groundwater pumped annually
o 55 million gallons of stormwater pumped annually
Investigations:waterquality
Measuring quality of pumped water as a comparison to water in Lake Hiawatha
o Water samples were collected from Lake Hiawatha, Pond E, and four monitoring wells in January 2016
o MPRB also used historic samples of water in Lake Hiawathao Concentrations of phosphorus in samples of pond, ground and
lake water were very similaro Total load of phosphorus from pumped water is less than 2.5% of
the annual load of phosphorus to the lakeo The impact of pumped water on the quality of water in Lake
Hiawatha is negligibleo Also analyzed groundwater and lake water for contaminants such
as volatile organic carbons and diesel range organics and did not detect any contamination
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Investigations:deepgroundwater
Assessing impacts on deep groundwatero An existing but rarely used deep well on the golf course was
energized to pump deep groundwater for 72 hours beginning on 2/16/2016, during which time 1.7 million gallons of water were pumped from the well into Lake Hiawatha
o During the pumping, data loggers in the monitoring wells were analyzed to determine if there was any drawdown in shallow groundwater
o There was no recorded change in the groundwater elevations in the monitoring wells indicating there is no direct relationship between shallow groundwater and deep groundwater that is impacted by the current pumping
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Investigation:waterlevelrecovery
Measuring the impacts on pond elevations without pumping
o A “short term recovery test” was performed from 12/31/2015 to 1/4/2016
o Pumps were turned off and water elevations in the pond were allowed to increase
o Pond elevations increased 1 foot in 92 hours (from an elevation of 808.8 to 809.8)
o Pumps were turned on at the end of the test periodo The test suggests, without pumping, the water elevation on
the golf course property would equalize with Lake Hiawatha
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Investigation:waterlevelrecovery
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• drawing is not to scale• elevations are approximate
Existing condition, pumps on
Investigation:waterlevelrecovery
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• drawing is not to scale• elevations are approximate
Potential condition, pumps off
PhaseOnefindings
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If water levels were allowed to rise to 812.8 under normal conditions with pumps turned off, based on the estimated basement floor elevations:
o There are approximately 9 at‐risk homes near the low spot at 19th Avenue and 44th Street
o Based on a typical groundwater gradient, there may be an additional 9 homes at‐risk in the watershed to the west of the golf course
PhaseOnefindings
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If water levels were allowed to rise to 812.8 under normal conditions with pumps turned off, based on the elevations across the golf course:
o As most fairways are at an elevation of about 811 to 812, large areas of the golf course would be inundated
o Because groundwater levels would likely be at or near the same elevation of the water on the golf course, a large area of soils outside of the inundated area would be saturated
PhaseOnefindings
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Lake Hiawatha
43RD ST E
28TH
AVE
S
17TH
AVE
S
18TH
AVE
S
CED
AR A
VE S
30TH
AVE
S
29TH
AVE
S
LONG
FELL
OW
AVE
44TH ST E
47TH ST E
45TH ST E
46TH ST E
19TH
AVE
S
27TH
AVE
S
26TH
AVE
25TH
AVE
24TH
AVE
21ST
AVE
20TH
AVE
23RD
AVE
22ND
AVE
STAN
DIS
H A
30TH
AVE
S
47TH ST E
29TH
AVE
S
44TH ST E
45TH ST E
27TH
AVE
S
46TH ST E
Legend812.8 Feet
813.8 Feet
Existing Open Water
OtherPhaseOneactivities
o Meeting with owners of potentially impacted properties
o Determining basement elevations of potentially impacted properties
o Coordinating with regulatory agencies to understand the process of updating the groundwater appropriations permit and other applicable requirements.
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PhaseTwoinvestigations
Original project goals remain valid, with two significant modifications
o Developing concepts to restore or reconfigure the golf course if pumping continues or to imagine other park configurations if pumping stops
o Improving the ecology of the creek through the golf course property
o Considering options for the pipe from East 43rd Street (north side) that empties into Lake Hiawatha
o Understanding fully the potential groundwater impacts on nearby private properties if pumping stops
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PhaseTwoinvestigationsandexplorations
Work will proceed in concert with City of Minneapolis Department of Public Works (DPW)
As appropriate, MPRB and DPW will engage other agencies and regulators to review findings and directions
We need to understand impacts beyond the areas considered in Phase One (the golf course and nearby private properties)
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Groundwaterappropriationspermit
City and MPRB staff met with MnDNR staff in Novembero Reviewed general outcomes of Phase One investigationso Described activities anticipated for Phase Twoo Asked for comments on a work plano Reviewed the status of the permit
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PhaseTwoprimaryissues
Framing regulatory parameters for pumping options
Determining specific effects of pumping scenarios on the golf course and nearby private properties
Understanding effects on water quality, ecology, and public infrastructure
Defining a preferred scenario on a reasonable timeline
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PhaseTwoinvestigationsandexplorations
Four major tasks are envisioned as a part of Phase Twoo Engaging internal and external resources to accomplish
Phase Twoo Updating elected officials, regulatory agencies, and the
public at the outset of Phase Twoo Conducting further investigations focused on the
implications of pumping and no pumping scenarioso Exploring options focused on
o Continued pumpingo Reduced pumpingo No pumping
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PhaseTwoinvestigationsandexplorations
Options will consider factors including:o Defining pumping volumes and review of permit allowanceso Impacts on golf operations and golf playo Water quality impacts on Lake Hiawatha and Minnehaha
Creek, and as appropriate on Lake Nokomiso Short‐ and long‐term ecologic impactso Impacts on nearby private propertieso Public infrastructure impactso Likelihood of achieving regulatory approvals
Exploration of options will result in the identification of a preferred scenario
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PhaseTwoscheduleandoutcomes
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TASK 1Engage internal and external resources
o Consultants engaged by December 2016
TASK 2Update officials, regulators, public
TASK 3Conduct further investigations
TASK 4Explore pumping options
SCHEDULE
OUTCOMES
o Public meeting on 29 November 2016
o Updates complete by December 2016
o Investigations completed by March 2017
o Preferred scenario identified by July 2017
o Day‐to‐day project management process defined
o Consultants engaged
o Updates completedo Status review with
MnDNR completed
o Baseline investigations supporting options accomplished
o Regulatory concerns identified
o Options framed for each scenario
o Review of options accomplished
o Preferred direction identified
Questions
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