The Water Withdrawal Assessment Process Context within regional water policy discussions Context...
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The Water Withdrawal Assessment The Water Withdrawal Assessment Process Process • Context within regional water policy Context within regional water policy discussions discussions – Aquatic ecosystems now a priority “user” Aquatic ecosystems now a priority “user” – No “Adverse Resource Impact” No “Adverse Resource Impact” – Ground- & Surface-water connections recognized Ground- & Surface-water connections recognized • Groundwater Conservation Advisory Council Groundwater Conservation Advisory Council – Convened by the legislature Convened by the legislature – Broadly representative of societal water use Broadly representative of societal water use interests interests – Charged with definitions, design of science-based Charged with definitions, design of science-based process and screening tool, and guidance on policy process and screening tool, and guidance on policy – National science review panel National science review panel
The Water Withdrawal Assessment Process Context within regional water policy discussions Context within regional water policy discussions –Aquatic ecosystems
The Water Withdrawal Assessment Process Context within regional
water policy discussions Context within regional water policy
discussions Aquatic ecosystems now a priority user No Adverse
Resource Impact Ground- & Surface-water connections recognized
Groundwater Conservation Advisory Council Groundwater Conservation
Advisory Council Convened by the legislature Broadly representative
of societal water use interests Charged with definitions, design of
science-based process and screening tool, and guidance on policy
National science review panel
Slide 2
The Flow Regime Paradigm -- There is a geography of flow
regimes -- Fish species are adapted to habitats controlled by
certain quantities of, and variability in, river flows Climate
GeologyLanduse Flow regime
HydraulicsChannelNutrientsTemperature
Slide 3
Michigan rivers naturally have different flow regimes, and thus
different habitat conditions, biological communities, sensitivity
to disturbance, and potential for fishery management.
Slide 4
Michigan Streams by Flow
Slide 5
Midwest Streams by Flow
Slide 6
Index Flow Stressful, low flow period
Slide 7
The Water Withdrawal Assessment Process Groundwater Stream Flow
Fish Populations Three Models Interact within the impact assessment
model Withdrawal Model - How much water is in the aquifer, is being
withdrawn, and from where and how it will affect stream flow
Streamflow Model - How much water is flowing in the stream during
summer low flow periods Fish Impact Model - What fish are in the
stream and what is the likely effect of removing water on those
groups of fish FeedsSupports
Slide 8
The Water Withdrawal Assessment Process This is the process
that the user goes though to see whether the proposed withdrawal is
OK or is likely to cause an adverse effect on fish populations This
is the process that the user goes though to see whether the
proposed withdrawal is OK or is likely to cause an adverse effect
on fish populations Screening Tool The Automated Analysis within
the model based on general, state-wide data for a given withdrawal
Screening Tool The Automated Analysis within the model based on
general, state-wide data for a given withdrawal Site Specific
Analysis Same process but using professional evaluation of
site-specific data on flow, geology or fish Site Specific Analysis
Same process but using professional evaluation of site-specific
data on flow, geology or fish
Slide 9
1. The Withdrawal Model Model needs to know how much water is
in the local aquifer Automatically determines where the nearest
streams are. Apportions the withdrawal effect between streams
Calculates the likely reduction in flow due to the proposed
withdrawal Rain and Snow Recharge to area
Slide 10
Characteristics of the Withdrawal Model Distance Matters
Distance Matters A well adjacent to a river will very quickly get
water either from water that would have gone to the river or
directly from the river A well farther from a river will get more
water from storage and require a longer time to affect the stream
Geology and Soil Matters Geology and Soil Matters Clay soils are
tight and water does not move easily Sandy soils are porous and
water flows quickly
Slide 11
2. The Streamflow Model Need to Know How Much Flow is in any
Stream Segment Index flow; low flow period in the year Look at the
segments where we know the flow (132 stream gauges in the State)
and extrapolate these to the streams that are not gauged Major
Factors Used Drainage Basin Size Forest Cover Geology and Soils
Precipitation
Slide 12
Index Flow Stressful, low flow period
Slide 13
Major Factors in the Analysis The geographic database contains
info for 11,000 distinct watersheds and streams Info on watershed
location, size, geology; and on stream flow, temperature, and fish
populations Resulting maps closely match field experiences
Slide 14
3. The Fish Response Model What fish populations live where in
the streams and how do they respond to flow reductions in the
summer (at low flow)
Slide 15
Slide 16
Smallmouth bass Fish habitat optima identified - Low-flow
yield, catchment area, and July mean temperature - 82 most common
species
Slide 17
Each fish species has a habitat optimum and suitability curve.
Abundance Habitat Gradient (Flow or Temperature for instance) For ~
60 fish species we determined these for 1) Catchment area, 2)
summer base-flow yield, and 3) July mean temperature. We assigned
scores of 4, 3, 2, 1, 0 (respectively) to each 0.5 standard
deviation increment away from the optimum for that habitat
variable. Optimum Habitat 4 represents best conditions 4 is 0.5 SD
3 is 0.5 to 1.0 SD 2 is 1.0 to 1.5 SD 1 is 1.5 to 2.0 SD 0 is >
2.0 SD
Slide 18
Below state median Above state median 2X state median Thriving
Characteristic Abundance
Slide 19
Streams Cold Cool Warm Lg RiversSm Rivers Cold Trans We grouped
Michigan streams into types and developed response models using an
average of ~ 20 specific segments per type 20 Cold Sm Rivers 20
Warm Streams X
Slide 20
All River Segment Types
Slide 21
What Can the Fish Curves Tell Us About Functional
Impairment?
Slide 22
Baseline or existing condition Some replacement of sensitive
species Some density changes in fish Notable replacement by
tolerant species Tolerant species dominant; ecological functions
altered Severe alteration of ecological structure and function
Interpretive criteria from Davies and Jackson 2006 What Can the
Fish Curves Tell Us About Functional Impairment?
Slide 23
ABCD Adverse Resource Impact Gradient of increasing risk
Interpreting the Fish Curves Characteristic Fish Thriving Fish 90%
80%