PROJ00148

• Contract/PO #: C150023
• Contractor Name: Ryan Gulch Reservoir Company
• Contract Type: Loan
• Water District: 4
• County: Larimer
• Bill Number: SB 99-173
• Loan Projects - Doc Type: Feasibility Study

,

Table of Contents

Certification ........................................................................................................................

Acknowledgments ...... .............................. .................................................. .... ...................... I

Executive Summary ............ ............. ........ ....................... ..................................................... II
Table of Contents .................................... ............................................................................. iii

Chapter I
Chapter II
Chapter III
A.
B.
C.
D.
E.

F.
G.

Chapter IV
A.

B.

C.

j

D.

. ,
i

Chapter V
A.

B.
C.

Introduction................................................................................................ ..
Description of Sponsoring Entity ...............................................................

BlJckground Information ....................... ..................................... ................

Previous Studies.................... ............................. ........................... .................
Study Area and Existing Facilities Description .............................................

Water Demands..............................................................................................
Project Lands ....................................................... ..........................................
Hydrology and Water Rights .........................................................................

E.I Flood Hydrology .................................................................................. ...
E.2 Water Rights ............................................................................................
Water Quality ......................... ... ............................................................. ........
Field Investigations....................... .................................................................

Formulation of Alternatives ........................................................................

Spillway Alternatives...................... ........................................................,......
Spillway Alternative S 1 - Roller Compacted Concrete ................................
Spillway Alternative S2 - Articulated Concrete Block with Training Walls
Spillway Alternative S3 - Articulated Concrete Block with Berm ...............
Spillway Alternative S4 - Right Abutment Riprap .......................................
Spillway Alternative S5 - Left Abutment Riprap..........................................
Seepage Comtrol Alternative .........................................................................
Embankment Alternative E1 _ Clay Liner.....................................................
Embankment Alternative E2 - Synthetic Liner .............................................
Outlet Works Alternative ............................................................... ................
Outlet Works Alternative 01 - Steel Sleeved Liner......................................

No-Action Alternative....................................................................................

Evaluation of Alternatives...........................................................................

Impacts .................................................................................. ......... ........... .....
A.l Man-Made Environmental Impacts.........................................................
A.2 Natural Environmental Impacts ..............................................................
A.3 Social Structure Impacts .........................................................................
Institutional Considerations...........................................................................

Comparative Evaluation.......... .......... .................i. ........ ............ ........... .... .... ...
C.I Spillway Alternatives ..............................................................................
Spillway Alternative S I - Roller Compacted Concrete .............................
Spillway Alternative S2 - Articulated Concrete Block with Training Walls
Spillway Alternative S3 - Articulated Concrete Block with Berm..............

C:\WORK\PROIECTS\RY AN\FEASREPORTlRY ANRPT DOC

III

I
4
6
6
6
6
7
7
7
9
9
9

10
10
10
II
11
12
12
12
12
12
13
13
13

33
33
33
33
34
34
34
34
34
35
38

M~hI7,1997