AlternativeCurrent ConditionsFlood StorageMulti-Purpose
(Hydropower) Total storage capacity (AF)080,000145,000 Reservoir
surface area (ac)NA1,0001,450 Bottom elevation (ft)NA1428.6
Spillway elevation (ft)NA1646.61696.6 Dam crest elevation
(ft)NA1666.61716.6 Dam crest length (ft)NA1,4501,800 Outlet
capacity (cfs)NA 2,000 Spillway length (ft)NA500 Spillway weir
coefficient 1 NA1.11 1 Spillway maximum capacity (cfs)NA49,640
Power plant minimum operating elevation (ft) NA 1606.6 Power plant
capacity (cfs)NA 732 Power plant tailwater elevation (ft)NA 1436.6
Table 3 Dam and Outlet Configuration for Alternatives. Notes: 1 The
spillway weir coefficient was calculated from the given spillway
length and a spillway capacity requirement of 50,000 cfs
Slide 4
DatesPower Release (cfs) October 1-November 23140 November
24-March 31732 April 1-September 30140 Table 7 Multi-Purpose
Reservoir Power Release Schedule
Slide 5
Reservoir Pool Elevation (NGVD + 1,000 ft) Description of
Release 1428.6 to 1594.5 20 cfs bypass release No power release
1594.5 to 1606.5 Ramp to 140 cfs bypass release (10 cfs per foot
elevation) No power release 1606.6 to 1631.6 No bypass release 140
cfs low power release 592 cfs high power release 1631.6 to 1657.0
Ramp to 1,268 cfs bypass release (50 cfs per foot elevation) 140
cfs low power release 592 cfs high power release 1657.0 to 1716.6
1,268 cfs bypass release 140 cfs low power release 592 cfs high
power release Table 8 Multi-Purpose Reservoir Overall Release
Schedule (November 24 to March 31)
Slide 6
Reservoir Pool Elevation (NGVD + 1000 ft) Description of
Release 1428.6 to 1594.5 20 cfs bypass release No power release
1594.5 to 1606.5 Ramp to 140 cfs bypass release (10 cfs per foot
elevation) No power release 1606.6 to 1631.6 No bypass release 140
cfs low power release 1631.6 to 1643.4 Ramp to 592 cfs bypass
release (50 cfs per foot elevation) 140 cfs low power release
1643.5 No bypass release 140 cfs low power release 592 cfs high
power release 1643.5 to 1668.9 Ramp to 1,268 cfs bypass release (50
cfs per foot elevation) 140 cfs low power release 592 cfs high
power release 1668.9 to 1716.6 1,268 cfs bypass release 140 cfs low
power release 592 cfs high power release Table 9 Multi-Purpose
Reservoir Overall Release Schedule (April 1 to November 23)
Slide 7
Flood Modeling
Slide 8
Figure 3 Reservoir Water Surface Elevation and Outflow 100-year
Event, Flood Storage Alternative
Slide 9
Figure 2 Comparison of Flood Storage Alternative to Current
Conditions 100-year Event, USGS Gage at Doty
Slide 10
EventEmptying Time (days) 100 year24 50 year21 10 year15 2007
flood50 Table 6 Flood Storage Reservoir Emptying Time after Flood
Events Notes: Time is calculated starting from the time when the
reservoir begins storing water (reservoir inflow > 2000 cfs) and
ending at the time when reservoir outflow is equal to reservoir
inflow.
Slide 11
Event Peak Flow (cfs) 1-Day Average Flow (cfs) 3-Day Average
Flow (cfs) 7-Day Average Flow (cfs)
CurrentFloodDiffCurrentFloodDiffCurrentFloodDiffCurrentFloodDiff
100-yr
39,35317,433-55.7%24,33110,914-55.1%13,6647,003-48.7%8,1924,941 -
39.7% 50-yr
32,56214,792-54.6%20,3989,473-53.6%11,8746,348-46.5%7,3444,631 -
36.9% 10-yr
19,8579,831-50.5%12,9376,740-47.9%8,2335,014-39.1%5,4723,941 -
28.0% Dec07
63,10025,861-59.0%41,39017,476-57.8%20,3109,224-54.6%11,3935,798 -
49.1% Table 5 Comparison of Flood Storage and Current Conditions
Modeling Results at the USGS Gage at Doty Notes: Current = current
conditions alternative Flood = flood storage alternative
Slide 12
Figure 14 1996 Flood Hydrograph at Mellen Street
Slide 13
Figure 19 1996 Flood Water Surface Elevation Profile, Existing
and Proposed
Slide 14
Figure 13 100-year Hydrograph at Mellen Street
Slide 15
Figure 15 100-year Flood Profile, Existing and Proposed
Slide 16
Figure 16 50-year Water Surface Elevation Profile, Existing and
Proposed
Slide 17
Figure 17 10-year Water Surface Elevation Profile, Existing and
Proposed
Slide 18
Figure 18 2-year Water Surface Elevation Profile, Existing and
Proposed
Slide 19
Flow Exceedance Analysis
Slide 20
Figure 7 Exceedance Curves for the Flood Storage and Current
Conditions Alternatives USGS Gage at Doty
Slide 21
Month Average MaximumMinimum 90% 50%10% Flood Current Flood
Current Flood Current Flood Current Flood Current FloodCurrent
Oct2232263,9825,77718 24 66 478 Nov1,0081,0287,10213,44422 89 583
2,7312,411 Dec1,3391,36717,22640,33250 248 7967673,0933,103
Jan1,3931,3708,24616,413166 319 1,0099292,9562,933
Feb1,0331,0209,12819,162133 219 658 2,5182,029
Mar8828675,3819,470100 268 645 1,8361,658 Apr585 6,23611,099114 220
392 1,1241,076 May273 2,171 79 113 212 506 Jun161 2,6022,60140 70
121 275 Jul67 387 22 35 60 103 Aug43 662 17 24 34 59 Sept60 2,321
16 21 30 86 Table 10 Comparison of Flood Control and Current
Conditions Alternatives Monthly Flow Statistics at the USGS Gage at
Doty Notes: Flood = flood storage alternative Current = current
conditions alternative
Slide 22
Month Average MaximumMinimum 90% 50%10% Flood Current Flood
Current Flood Current Flood Current Flood Current FloodCurrent
Oct79880014,60516,400181 229 390 1,694 Nov3,9393,96032,66138,400177
473 2,325 10,20310,200 Dec6,1266,15738,79461,900327 1,380
4,1654,03514,09914,400 Jan6,6456,61750,33358,5001,010 1,843
5,2074,99513,20112,990 Feb5,2455,23554,16664,200709 1,482 3,570
10,48610,300 Mar4,2604,24619,90821,900601 1,361 3,235 8,6848,593
Apr3,0043,00734,21538,000670 1,260 2,225 5,313 May1,5331,5317,360
394 706 1,220 2,809 Jun969 5,810 234 437 775 1,641 Jul400 1,340 151
235 361 622 Aug267 2,100 117 177 236 372 Sept344 3,600 128 199 272
457 Table 13 Comparison of Flood Control and Current Conditions
Alternatives Monthly Flow Statistics at the USGS Gage at Grand
Mound Notes: Flood = flood storage alternative Current = current
conditions alternative
Slide 23
Month Average MaximumMinimum 90% 50%10% Flood Current Flood
Current Flood Current Flood Current Flood Current FloodCurrent Oct
1,055 15,100 282 335 546 2,259 Nov 5,2715,29432,91638,800293 593
3,250 13,84213,800 Dec 8,6328,66045,69367,300538 2,131
6,1005,93519,60420,170 Jan 9,5179,48154,57860,3001,580 2,900
7,6707,37019,27019,190 Feb 7,764 52,37555,0001,180 2,246
5,7905,78016,36016,180 Mar 6,2336,22028,81529,6001,090 2,200 4,945
11,800 Apr 4,3364,34132,01535,8001,120 1,960 3,350 7,270 May
2,2142,2099,570 737 1,030 1,860 3,919 Jun 1,393 7,730 352 680 1,110
2,401 Jul 625 1,810 258 386 568 924 Aug 427 2,580 182 311 407 558
Sept 487 5,160 183 307 403 608 Table 14 Comparison of Flood Control
and Current Conditions Alternatives Monthly Flow Statistics at the
USGS Gage at Porter Notes: Flood = flood storage alternative
Current = current conditions alternative
Slide 24
Figure 5 Comparison of Multi-purpose Alternative to Gage
Records USGS Gage at Doty Water Years 2001 to 2003
Slide 25
Figure 6 Reservoir Results for Multi-purpose Alternative Water
Years 2001 to 2003
Slide 26
Figure 8 Exceedance Curves for the Multi-purpose and Current
Conditions Alternatives USGS Gage at Doty
Slide 27
Month Average MaximumMinimum 90% 50%10% Multi Current Multi
Current Multi Current Multi Current Multi Current MultiCurrent Oct
180 226 2,662 5,777 28 18 48 24 117 66 337 478 Nov 756 1,028 6,303
13,444 33 22 104 89 427 583 1,939 2,411 Dec 1,392 1,367 16,393
40,332 105 50 311 248 1,100 767 2,585 3,103 Jan 1,349 1,370 7,092
16,413 198 166 351 319 1,178 929 2,404 2,933 Feb 1,129 1,020 8,795
19,162 179 133 231 219 992 658 1,967 2,029 Mar 933 867 4,478 9,470
153 100 280 268 942 645 1,429 1,658 Apr 416 585 4,479 11,099 164
114 220 321 392 702 1,076 May 296 273 1,045 2,171 168 79 182 113
234 212 501 506 Jun 210 161 1,161 2,601 154 40 165 70 184 121 288
275 Jul 160 67 291 387 90 22 139 35 161 60 178 103 Aug 138 43 338
662 54 17 82 24 152 34 160 59 Sept 123 60 991 2,321 32 16 53 21 122
30 163 86 Table 11 Comparison of Multi-Purpose and Current
Conditions Alternatives Monthly Flow Statistics at the USGS Gage at
Doty Notes: Multi = multi-purpose alternative Current = current
conditions alternative
Slide 28
Month Average MaximumMinimum 90% 50%10% Multi Current Multi
Current Multi Current Multi Current Multi Current MultiCurrent Oct
76380013,28516,4002111812602294373901,5291,694 Nov
3,6773,96032,50438,4002051774774732,1122,3259,44410,200 Dec
6,1826,15737,96161,9003823271,6051,3804,4054,03513,32614,400 Jan
6,6026,61749,17958,5001,0361,0101,9101,8435,1684,99512,74012,990
Feb 5,3335,23553,83364,2007547091,4881,4823,9063,57010,19310,300
Mar 4,3154,24619,43121,9006546011,3821,3613,5253,2358,2948,593 Apr
2,8423,00732,35638,0007206701,2591,2602,1782,2254,7705,313 May
1,5531,5316,2227,3604833947657061,2681,2202,8302,809 Jun
1,0179695,3955,8103482345264378297751,6481,641 Jul
4924001,2661,340225151335235462361693622 Aug
3632671,7402,100155117253177348236477372 Sept
4083442,6023,600165128247199364272529457 Table 15 Comparison of
Multi-Purpose and Current Conditions Alternatives Monthly Flow
Statistics at the USGS Gage at Grand Mound Notes: Multi =
multi-purpose alternative Current = current conditions
alternative
Slide 29
Month Average MaximumMinimum 90% 50%10% Multi Current Multi
Current Multi Current Multi Current Multi Current MultiCurrent Oct
1,0261,05514,59515,1003022823623355855462,1332,259 Nov
5,0035,29432,35438,8003212936125933,1073,25012,68613,800 Dec
8,6888,66045,50167,3005935382,4412,1316,3395,93519,01620,170 Jan
9,4749,48153,34360,3001,5791,5802,9122,9007,5507,37018,69819,190
Feb
7,8457,76451,40655,0001,2251,1802,2522,2465,9845,78015,70316,180
Mar
6,2926,22028,81529,6001,1421,0902,1822,2005,2274,94511,59111,800
Apr 4,1794,34130,15635,8001,1701,1201,9531,9603,3173,3506,8487,270
May 2,2302,2098,4329,5708187371,0881,0301,8981,8603,8493,919 Jun
1,4401,3937,6807,7304643527756801,1631,1102,3992,401 Jul
7176251,8311,810333258493386666568998924 Aug
5244272,3202,580221182385311522407660558 Sept
5514875,1225,160221183348307494403688608 Table 16 Comparison of
Multi-Purpose and Current Conditions Alternatives Monthly Flow
Statistics at the USGS Gage at Porter Notes: Multi = multi-purpose
alternative Current = current conditions alternative
Slide 30
Water Quality/Temperature Modeling
Slide 31
Figure 20 Inflow Hydrographs Used at the Upstream Boundary
(Doty Gage) for Temperature Modeling
Slide 32
Locations of Temperature Probes/Water Quality Data
Slide 33
Slide 34
Slide 35
Figure 25 Riverwide flows simulated on July 15, 2010 for the
baseline and multi-purpose reservoir scenarios
Slide 36
Figure 26 Riverwide flows simulated on August 22, 2010 for the
baseline and multi-purpose reservoir scenarios
Slide 37
Example of Reservoir Output CE QUAL 2 Model
Slide 38
Calibration of Water Quality Model
Slide 39
Slide 40
Slide 41
Slide 42
Slide 43
Slide 44
Slide 45
Number of days Average Water Column Temperature Exceeds 18C For
Various Reaches