Draft EIS_072312.pdf - Middle Fork American River Project ...

More documents

Recommendations

Info

106 October November December Proposed Action (Alternative 1, when different from proposed flows) January February March 1-14 Location Water Year Type a below Oxbow 75 75 75 75 75 75 125 125 125 125 100 100 100 100 75 75 powerhouse C (125) (140) (140) (140) (140) (140) (160) (160) (160) (160) (160) (160) (160) (160) (150) (150) 90 90 90 90 90 90 210 210 210 210 150 150 150 150 120 90 D (140) (145) (145) (145) (145) (145) (210) (210) (200) (200) (160) (160) 120 120 120 120 120 120 290 290 290 290 200 200 200 200 160 120 BN (165) (185) (185) (185) (185) (185) (245) (245) (245) (245) (200) (200) 150 150 150 150 150 150 375 375 375 375 250 250 250 250 200 150 AN (165) (225) (225) (225) (225) (225) (300) (300) (300) (300) (250) (250) 200 200 200 200 200 200 450 450 450 450 300 300 300 300 250 200 W (250) (250) (250) (250) (250) (350) (350) (350) (350) (300) (300) Middle Fork E 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 American River below Ralston All other 3 3 3 3 3 3 3 (25) 3 (25) 3 (25) 3 (25) 3 (10) 3 (10) 3 (10) 3 (10) 3 (10) 3 (10) afterbay dam years Notes: Minimum instream flows in parentheses are flows included in Alternative 1 and not the proposed project. Grey-shaded cells indicate the minimum flow is the specified minimum flow or natural inflow to the bypassed reach, whichever is less a Water year types: E = Extreme critical, C = Critical, D = Dry, BN = Below normal, AN = Above normal, W = Wet b ND = no diversion. If July 1 inflow to the Duncan Creek diversion exceeds the May minimum instream flow requirement, then the July minimum instream flow requirement will be equal to the May minimum instream flow requirement or natural inflow, whichever is less. The intent is to avoid a large flow spike at the end of the diversion season on July 1. March 15-31 April May 1–14 May 15–31 June 1–14 June 15–30 July August Sept. 1–15 Sept. 15–30
20120723-4002 FERC PDF (Unofficial) 07/23/2012 Minimum flow increases in the peaking and bypassed reaches in the wettest water year types would increase wetted stream perimeter, which may increase habitat area and habitat diversity in some reaches for fish and aquatic invertebrates. Increased edge habitat may improve rearing success of YOY fish in wet water years if shallow water or cover is available to increase their ability to avoid aquatic and terrestrial predation. Higher minimum flows should provide more area for aquatic macroinvertebrate communities that make up a large portion of the diet of trout and other fish. The range of proposed minimum flows in the peaking reach would be from 75 to 450 cfs, whereas the Alternative 1 minimum flows would range from 90 to 450 cfs. However, many of the Alternative 1 minimum flows would be from 15 to 100 cfs higher than the comparable proposed minimum flows for comparable water years and time frames. For the reasons stated in the previous paragraph, this prevailing higher minimum flow would result in the Alternative 1 regime providing minor habitat enhancements compared with the proposed flow regime. However, we expect the primary factor that would limit the quality and quantity of aquatic habitat in the peaking reach to be flow fluctuations, rather than minimum flows. Daily peaking flow fluctuations would be maintained under both action alternatives, and effects of the new minimum flow regime in the peaking reach on fish and other aquatic biota are expected to be negligible because changes in wetted habitat area would be of very short duration and likely insufficient to affect behavior (e.g., foraging), food availability, or production of aquatic biota. Typically, the period of snowmelt and high runoff occurs between April through mid-June in the basin and the spring pulse flows in the action alternatives reflect this timing. Restoring flows that mimic the spring snowmelt pulse may provide benefits to the aquatic community by helping to maintain a variety of seasonal life-history behaviors. Spring minimum flows would be substantially higher than under existing conditions in all water-year types under both action alternatives and, when coupled with the pulse flow releases (see section 3.3.1.2, Geologic and Soils Resources, table 3.3.1-2), would provide flow changes that simulate those found under unregulated conditions during the seasonal snowmelt period. Both the proposed and Alternative 1 minimum flows would enhance flow conditions for spawning by resident rainbow trout during spring (i.e., mid-March to June), based on the results of PCWA’s instream flow analysis (PCWA, 2010b). Higher spring flows may provide access to additional spawning or rearing habitat but may also act to scour redds in some years, both of which occur under natural stream conditions. Precipitation in the Middle Fork American River watershed has high inter-annual variation; water-year types tend to be either wet or dry, with few years receiving “average” precipitation. Under existing conditions, no provision is made for within-year or between-year variation in flows to reflect local seasonal changes and water year types. Many fish and aquatic macroinvertebrate species may use changes in flows as cues for behaviors such as spawning or movements into appropriate winter or summer habitat. Year-to-year variations in flows may maintain species diversity by benefiting certain species in wet years and others in dry years. Western streams with intact seasonal flow variation are believed to be more resistant to invasion by fish from eastern U.S. streams 107
Page 1 and 2:
20120723-4002 FERC PDF (Unofficial)
Page 3 and 4:
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
41 Table 3.3.1-1. Average number of
Page 73 and 74:
43 Site/Release Location Gravel Ini
Page 75 and 76:
45 a Q 1 - TSR, Table G-1 (PCWA, 20
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86: 20120723-4002 FERC PDF (Unofficial)
Page 99 and 100: 69 Table 3.3.2-3. Hydrology for sel
Page 101 and 102: 71 Exceedances and Summary Statisti
Page 121 and 122: 91 Figure 3.3.2-6. Fish passage bar
Page 135: 105 Location American River below M
Page 165 and 166: 135 Species Name Status a Butte Cou
Page 175 and 176: 145 Table 3.3.3-5. Special-status w
Page 177 and 178: 147 Species Name Status Habitat Occ
Page 187 and 188:
157 Species Name Status Habitat Occ
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
195 Figure 3.3.5-1. French Meadows
Page 227 and 228:
197 Figure 3.3.5-3. Long Canyon, re
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
253 Table 3.3.6-1. Archaeological a
Page 285 and 286:
255 Resource Number Type a Descript
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
275 Table 4-2. Summary of annual co
Page 307 and 308:
Page 309 and 310:
279 Enhancement/Mitigation Measures
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
303 c Base 2010 costs were provided
Page 335 and 336:
Page 337 and 338:
307 Resource No-Action Alternative
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
319 Table 5-2. Staff-recommended mi
Page 351 and 352:
321 Location Middle Fork American R
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Page 401 and 402:
Page 403 and 404:
A-1
Page 405 and 406:
A-3
Page 407 and 408:
Page 409 and 410:
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Page 417 and 418:
Page 419:
show all

Draft EIS_072312.pdf - Middle Fork American River Project ...

Create successful ePaper yourself

Delete template?

Save as template?