FLOOD10363 ‎(2)‎

• County: Gunnison
• Community: Gunnison County
• Stream Name: East River, Cement Creek, Alkali Creek, Ohio Creek
• Title: Gunnison County Flood Hydrology, Contract # W99-D-0018 Final Report
• Date: 11/1/2004
• Prepared For: US Army Corps of Engineers, CWCB and Gunnison County
• Prepared By: Tetra Tech, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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TABLE OF CONTENTS

EXECUTIVE SUMMARy.... ........ ... ... .... .... .... ......................... ............. ............. ......... ......... ... ............................ V

1.0
2.0
3.0
4.0
4.1
4.2
4.3
5.0
5.1

INTRODUCTION. ........ ... ....... ....... ............. ............................. .... .... ............... ............ ................ ... .......1

STUDY AREA ......... ..... ....... ........ ..................................................... ................. ...... ....... ............ ..........2

LITERA TURE REVIEW ................................................................................................. ....... ....... ...... 7

METHODS.......................................................................................................................................... .. 7

REACHES WITH SUFFICIENT STREAMGAGE DA TA ..................................................................7
4.1.1 Snowmelt, Rainfall, and Rain on Snow Events..............................................................................8
REACHES WITH INSUFFICIENT STREAMGAGE DA TA ..............................................................9
EFFECTS OF TA YLORPARK RESERVOIR REGULA TION........................................................ 12

INDIVIDUAL REA CHES .................................................................................................................. 14

REACH 2- SLA TE RIVER TO CONFLUENCE WITH EAST RIVER ........................................... 14

5.1.1 Description of Reach 2 .............................................................................................................. 14
5.1.2 Flood Records for Reach 2 ........................................................................................................ 14

5.1.3 Results for Reach 2 ...... .............. ........... ....... ................... ......... ................................................. 15
5.2 REACH 3 - EAST RIVER FROM SLA TE RIVER TO CEMENT CREEK ...................................... 17

5.2.1 Description of Reach 3 .............................................................................................................. 17
5.2.2 Flood Records for Reach 3 ........................................................................................................ 17

5.2.3 Results for Reach 3 ........... ...... ........... ................. .............. ........... ............................................. 18
5.3 REACH 4 - EAST RIVER FROM CEMENT CREEK TO ALKALI CREEK.... ...... ................ ........ 21

5.3.1 Description of Reach 4.................. ................. .......................... ............................ ..................... 21

5.3.2 Flood Records for Reach 4 ........................................................ ................................................ 21

5.3.3 Results for Reach 4 . ................ ............. ........ ......... .................................. .................................. 21
5.4 REACH 5 -EAST RIVER FROM ALKALI CREEK TOALMONT ................................................24

5.4.1 Description of Reach 5........................... .... ............................................ ................................... 24

5.4.2 Flood Records for Reach 5 ....................................................................................... ................. 24

5.4.3 Results for Reach 5 ................................................................................................................... 24
5.4.4 Review of Drainage Area versus Flow and Contributions from Alkali Creek .............................. 26
5.5 REACH 6- GUNNISON RIVERFROMALMONT TO OHIO CREEK ..........................................26

5.5.1 Description of Reach 6........................... .... .................... ......................... ............ ....................... 26

5.5.2 Flood Records for Reach 6............................................... .........................................................26

5.5.3 Results for Reach 6 ................................................................... .................................... ............28
5.6 REACH 7 - omo CREEK UPSTREAM OF THE CONFLUENCE WITH THE

GUNNISON RIVER..... ................... ........ ..... ....... .......... .............. ............ ... ...... .... ..... ... ...... .......... ....... 30

5.6.1 Description of Reach 7........... .............. ........................... ........................... ........................ ....... 30

5.6.2 Flood Records for Reach 7........................................................................ ................................ 30

5.6.3 Results for Reach 7 ... ....................................................................... ........................ ................. 30
5.7 REACH 8 - TOMICHI CREEK FROM THE GUNNISON RIVER TO THE GUNNISON

AIRPORT........... ........ ..... .... ......... ... ................ .... ... ...... ............ ....................... ..... .............................. 33

5.7.1 Description of Reach 8.... ............................................................................................. .......... ...33
5.7.2 Flood Records for Reach 8........................................................................................................33
5.7.3 Resultsfor Reach 8 ...................................................................................................................33
5.8 REACH9-GUNNISONRIVERFROMOHIO CREEK TO TOMICHI CREEK............................ 36
5.8.1 Description of Reach 9. ............ .............. ............... .................... ........... ............. ............... ......... 36
5.8.2 Flood Records for Reach 9........................................................................................................36
5.8.3 Results for Reach 9 ................................................................................................................... 37
5.9 TAYLOR RIVERA T ALMONT ........................................................................................................ 40
5.9.1 Description of Taylor River at Almont ....................................................................................... 40