Understanding_Instream_Flow_Incremental_Methodology

Report
Understanding Instream Flow
Incremental Methodology (IFIM)
Joey Kleiner
IFIM: Instream Flow Incremental Methodology
• The goal of an IFIM study is to show
the relationship between stream
flows and available aquatic habitat
• This Flow:Habitat relationship is
necessary for assessing potential
downstream impacts on habitat resulting
from upstream flow alterations
• A main product of an IFIM study is the
Weighted Usable Area (WUA) tablean index showing habitat suitability
for a given species over a range of
flows
Steps in the IFIM Process
1)
2)
3)
4)
5)
6)
Habitat identification
Transect selection
Species selection, habitat suitability criteria (HSC) compilation
Collection of field hydraulic and habitat data
Physical Habitat Simulation System (PHABSIM) model
PHABSIM output of “Weighted Usable Area” (WUA)
The Formation of Fish Habitat
• Fish habitat is dependent on:
• Depth
• Velocity
• River bottom conditions
(substrate/cover)
• Depth and velocity conditions
change with increasing flow
• Example: Riffles, runs, pools
The Mapping of Fish Habitat
• The first step in an IFIM study is the identification of aquatic habitats within the
study area
• The stream is divided into
“study reaches” at points
where significant changes in
channel morphology or flow
occur
• The primary types of
mesohabitats within these
reaches need to be identified
to facilitate transect site
selection
The Mapping of Fish Habitat (cont.)
• Habitat mapping is achieved through the use of existing institutional knowledge,
aerial photographs, GIS, GPS, and site-specific data obtained through “float trips”
Transect Locations
• Once the river reaches and
habitat types are identified and
mapped, transect locations for
the collection of field hydraulic
data are determined
• Transects are located in areas
representative of the
hydraulic/habitat conditions
observed in that reach
Field Data Collection
• Physical Habitat Simulation (PHABSIM) software is used to simulate the
relationship between streamflow and habitat for various species and life
stages of fish
• Data collected in the field at each transect location is used to calibrate
PHABSIM for the study reach of interest
• Data is collected at sampling stations/cells equally spaced along each
transect
• Data collected at each cell include:
• Water surface elevation (WSE)
• Water velocity
• Substrate/cover
Field Data Collection (Cont.)
• WSE and velocity data are typically collected at each transect under 3 different “target
flows” (low flow, medium flow, high flow)
• The target flows observed at the transects are achieved by altering dam releases upstream
• Example of target flows: 50, 150, and 300 cfs (measured by a USGS gage within the study reach)
• By entering the measurements taken
at 3 flows, PHABSIM is able to
interpolate WSE and velocity values
for flows other than the 3 observed in
the field
Field Data Collection (Cont.)
• Cover/substrate measurements
are taken during the lowest
target flow
• Codes for cover/substrate are
assigned to each cell along a
transect
Species Selection and HSC
• A set of fish species needs to be selected for
Flow:Habitat analysis
• The species selected must be present within the
study reach
• The species chosen are usually the ones most
affected by changes in flow
• Each species has corresponding Habitat
Suitability Criteria (HSC) that can be gathered
from existing sources
• HSC quantify habitat quality for each species/life
stage based on flow velocity, depth of the water
column and substrate/cover
• HSC utilize a preference index ranging from 0
(least preferred) to 1 (most preferred)
PHABSIM Development
• A hydraulic model within PHABSIM is created for each study transect
• The hydraulic model consists of a water surface model and a velocity model
• The water surface and velocity models are developed and calibrated using the 3 data sets
obtained in the field (1 data set from each of the 3 target flows)
• The calibrated hydraulic model is able to
simulate WSE and velocity values at each cell
along the transect for any flow value
• The hydraulic model at each transect is
combined with the HSC to produce a WUA
table showing the Flow:Habitat relationship
at that transect
PHABSIM Development (Cont.)
• HSC for water depths, water velocities and substrate/cover are used to rank the
suitability of each model cell in a transect
• This uses a multiplicative approach where suitability indexes (on a scale from 0.0 to 1.0) for a single
cell in a transect are multiplied together (depth*velocity*substrate) to produce a composite
suitability score for that cell (0.0 to 1.0)
• The suitability score of a cell is used to weight the area of that cell to produce a “Weighted usable
area” (WUA) value for that cell
• The weighted values for all cells in a transect are summed to produce a total WUA for that transect
WUA = suitability-weighted samples of area
•
WUA is an index to the microhabitat availability
WUA Development within PHABSIM
• By repeating this process for multiple species/lifestages over an entire range of
flows, a WUA table can be produced for each transect displaying the flow:habitat
relationship for each species/lifestage of interest
• The WUA tables from each transect in a reach can be averaged together using
weighting factors to produce a single WUA table representative of the entire
reach
• WUA tables from each transect are weighted so that each transect's
contribution to the reach-WUA is indicative of the amount of each habitat
type (% area) present in the reach
• Area weighting factors are determined during the development of the habitat
maps
WUA Development within PHABSIM (Cont.)
• Weighting transect-WUAs to produce a single reach-WUA table:
% of each habitat type present in a
single reach
Weighting factors for each transect in the reach
WUA Example
WUA Example
WUA (ft²/1,000 ft stream)
Smallmouth Bass
N Hogsucker
RedBSun Shallow Guild
Deep Guild
Juvenile Adult
Spawning Adult
Spawning Spawning Slow
Fast
Slow
Fast
10
8,650
4,062
18,545
1,585
112
19,431
8,020
288 17,310 1,172
20
13,381
8,447
18,820
2,071
176
19,960
4,740
693 18,889 2,536
40
22,200
16,204
18,799
3,537
293
19,972
2,488 1,137 21,407 5,261
60
28,774
20,791
18,726
5,323
394
19,880
1,643 1,964 23,420 7,969
80
32,940
22,872
18,496
7,642
482
19,876
1,532 2,631 25,292 10,168
100
36,522
24,433
17,592
10,083
574
19,626
1,479 2,807 26,489 12,558
120
39,761
25,291
16,474
13,036
684
19,183
1,644 3,136 27,450 15,079
160
44,456
26,838
13,635
19,659
893
16,465
1,062 3,354 28,132 20,133
200
47,555
27,499
9,493
26,700
1,096
13,042
667 2,065 27,429 24,033
250
49,959
28,079
7,368
33,427
1,247
11,139
615 1,564 26,722 27,576
300
51,581
28,710
6,000
39,508
1,379
9,454
430 1,071 25,607 30,227
350
52,257
28,869
4,792
44,866
1,456
7,854
486
737 24,197 30,935
400
51,643
28,429
3,887
49,235
1,498
6,617
546
611 22,672 30,704
450
50,249
27,458
3,261
52,640
1,477
5,411
645
517 20,851 29,608
500
48,364
26,438
2,821
55,144
1,407
4,514
484
413 19,294 28,123
550
46,047
25,640
2,554
56,623
1,322
3,889
334
333 17,737 26,710
600
44,087
24,248
2,144
57,514
1,201
3,229
189
279 16,570 25,499
650
42,233
23,011
1,925
58,020
1,099
2,898
155
197 15,305 23,741
700
40,196
22,018
1,769
58,065
976
2,565
173
154 14,093 22,428
750
38,186
20,711
1,503
57,884
831
2,121
196
125 12,972 20,835
800
36,218
19,469
1,392
57,521
661
1,875
216
84 12,034 19,426
900
33,366
17,012
1,114
56,349
469
1,557
186
51 10,274 16,857
1,000
29,379
14,898
962
54,663
329
1,339
122
31
8,706 14,519
1,100
26,655
13,299
793
52,923
197
1,178
89
24
7,588 12,331
Flow
(cfs)
WUA Example
WUA (ft²/1,000 ft stream)
Smallmouth Bass
N Hogsucker
RedBSun Shallow Guild
Deep Guild
Juvenile Adult
Spawning Adult
Spawning Spawning Slow
Fast
Slow
Fast
10
8,650
4,062
18,545
1,585
112
19,431
8,020
288 17,310 1,172
20
13,381
8,447
18,820
2,071
176
19,960
4,740
693 18,889 2,536
40
22,200
16,204
18,799
3,537
293
19,972
2,488 1,137 21,407 5,261
60
28,774
20,791
18,726
5,323
394
19,880
1,643 1,964 23,420 7,969
80
32,940
22,872
18,496
7,642
482
19,876
1,532 2,631 25,292 10,168
100
36,522
24,433
17,592
10,083
574
19,626
1,479 2,807 26,489 12,558
120
39,761
25,291
16,474
13,036
684
19,183
1,644 3,136 27,450 15,079
160
44,456
26,838
13,635
19,659
893
16,465
1,062 3,354 28,132 20,133
200
47,555
27,499
9,493
26,700
1,096
13,042
667 2,065 27,429 24,033
250
49,959
28,079
7,368
33,427
1,247
11,139
615 1,564 26,722 27,576
300
51,581
28,710
6,000
39,508
1,379
9,454
430 1,071 25,607 30,227
350
52,257
28,869
4,792
44,866
1,456
7,854
486
737 24,197 30,935
400
51,643
28,429
3,887
49,235
1,498
6,617
546
611 22,672 30,704
450
50,249
27,458
3,261
52,640
1,477
5,411
645
517 20,851 29,608
500
48,364
26,438
2,821
55,144
1,407
4,514
484
413 19,294 28,123
550
46,047
25,640
2,554
56,623
1,322
3,889
334
333 17,737 26,710
600
44,087
24,248
2,144
57,514
1,201
3,229
189
279 16,570 25,499
650
42,233
23,011
1,925
58,020
1,099
2,898
155
197 15,305 23,741
700
40,196
22,018
1,769
58,065
976
2,565
173
154 14,093 22,428
750
38,186
20,711
1,503
57,884
831
2,121
196
125 12,972 20,835
800
36,218
19,469
1,392
57,521
661
1,875
216
84 12,034 19,426
900
33,366
17,012
1,114
56,349
469
1,557
186
51 10,274 16,857
1,000
29,379
14,898
962
54,663
329
1,339
122
31
8,706 14,519
1,100
26,655
13,299
793
52,923
197
1,178
89
24
7,588 12,331
Flow
(cfs)
Sources:
Appomattox River Instream Flow (IFIM) Study: George F. Brasfield Dam to Harvell Dam, Final Report. Hunt Valley, MD: EA
Engineering, Science, and Technology, Inc., 2012
http://deq2.bse.vt.edu/sifnwiki/images/4/4f/G_Appomattox_River_Instream_Flow_IFIM_Study.pdf
Averett et. al. Stream Habitat Modeling to Support Water Management Decisions for the North Fork Shenandoah River,
Virginia, Final Report. Blacksburg, VA: Virginia Tech Dept. of Fisheries & Wildlife Sciences, 2004
http://deq3.bse.vt.edu/sifnwiki/images/f/fc/Ifim_nf_shen_doc.pdf
Bovee, K. D. et al. Stream Habitat Analysis Using the Instream Flow Incremental Methodology. Fort Collins, CO: U.S.
Geological Survey, 1998 http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA361209
Instream Flow Incremental Methodology (IFIM) Studies on the North Anna and Pamunkey Rivers, Virginia, Final
Report. Sparks, MD: EA Engineering, Science, and Technology, Inc., 2009
http://deq3.bse.vt.edu/misc/ifim_northanna_notebook.pdf
Krstolic, J.L., and Ramey, R.C. South Fork Shenandoah River habitat-flow modeling to determine ecological and recreational
characteristics during low-flow periods: U.S. Geological Survey Scientific Investigations Report 2012–5081, 64 p.
2012 http://pubs.usgs.gov/sir/2012/5081/pdf/sir2012-5081.pdf
Payne, T. et. al. Appalachian Power Company Claytor Hydroelectric Project No. 793-018, Instream Flow Needs Study, Final
Report. Arcata, California: Thomas R. Payne & Associates, 2008.
http://www.claytorhydro.com/documents/studyReportsDocs/ClaytorIFNStudy-FinalReport12-30- 08.pdf
Schreiner et. al. Habitat Assessment of the Potomac River From Little Falls to Seneca Pool, Final Report. Columbia, MD: Versar,
Inc., 2003 http://esm.versar.com/PPRP/potomac/2002report.htm
Stalnaker, C. et al. The Instream Flow Incremental Methodology, A Primer for IFIM. U.S. Dept. of the Interior Report 29, 1995.
https://www.fort.usgs.gov/sites/default/files/products/publications/2422/2422.pdf

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