FLOOD04873

• Designation Number: 359
• County: Archuleta
• Community: Pagosa Springs
• Stream Name: San Juan River and McCabe Creek
• Basin: San Juan/Dolores
• Title: Flood Hazard Analysis - San Juan River and McCabe Creek in the vicinity of Pagosa Springs, Archuleta County, Colorado
• Date: 9/1/1977
• Designation Date: 5/1/1994
• Floodplain - Doc Type: Floodplain Report/Masterplan

TABULATION OF ELEVATION REFERENCE MARKS

Hydrology and Hydraulics

Reference
Mark
Number El~vation

14
16
23
9
10
12
13
22A
30
31
34
35
36
40
42
43
47
48
51
53
58
59
60
104
67
68
107
108
111

7. 142.70
7.160.19
7,069.45
7,160.58
7,053.61
7.058.21
7,063.73
7.100.96
7.094.28
7,098.64
7, 106. 34
7,124.34
7,146.12
7,194.33
7.196.72
7,202.86
7.245.50
7,258.57
7,223.67
7.301.11'
7,336.44
7.337.15
7. 341. 58
7.377.84
7.352.11
7.366.80
7,419.40
7,433.23
7.488.75

Locat i on

F1Qop Hazard Map
Sheet Number

Hydrology - Two different methods of determining peak discharge values

were used: Streamgage record analysis, and synthetic hydrograph analysis.

These methods apply to the San Juan River segment and McCabe Creek

NELLIE O'NEAL RESIDENCE (USGS-Bench Mark)
S.E. CORNER E.E. SMITH PROPERTY
TOWN PARK, NEXT TO JAYCEE'S BUILDING
COUNTY ROAD, ENTRANCE TO GOODMAN BARN 1
NEXT TO LOUIS TORNATORE RESIDENCE ON 6TH ST. 2
6TH ST. NEXT TO SAN JUAN RIVER N OF NAVAJO ST 2
6TH ST. V.A. POMA PROPERTY & DURANGO ST. 2
PARK ST. BACK OF SPA PROPERTY 2
BACK OF SAN JUAN MOTEL CAB I NS 3
BACK OF CIRCLE K STORE
COLO. ROW SIGN N. OF Y 160 & 84 ~
SAN JUAN LBR. CO. ACCESS ROAD N. OF LOG POND 3
S.W. END FORMWALT RANCH 4
ACROSS FROM ZESCH CABINS 4
ACROSS FROM PAUL DAY RES I DENCE 4
ACROSS FROM DAY SAWMILL 5
COLO ROW APPROX. 1/4 MILE N. HARMAN CLARK RES 5
ACROSS FROM HENCE BARROW ROAD ENTRANCE 5
N. WOLF CREEK IND. NEXT TO ROW FENCE 6
COLO. ROW N. WOLF IND. 6
HESS PROPERTY 7
HESS PROPERTY 7
U.S.F.S. JOINING MASCO & HESS 8
COLO. ROW N. OF GODFREY RESIDENCE 8
S.J. RIVER DEV. PROPERTY ACROSS RIVER BY LOOP 9
DITCH HEAD GATE BY PARK 9
COLO. ROW BY GRIFFITH RESIDENCE 9
COLO. ROW N. GRIFFITH RESIDENCE 9
COLO. ROW N. MASCO RES I DENCE 9

segment respectively.

Records from three streamgages were used on the San Juan River. These

gages are located at Pagosa Springs and on each of the two main forks of

the river above the study area, Peak discharge - frequency data were

developed from the streamgage analyses. Procedures described in the

U. S. Water Resources Council, Bulletin No. 17, using the Log Pearson

III frequency distribution. were the primary guidelines for determining

flood flow frequencies. In accordance with recommendations from the

Colorado Water Conservation Board. Bulletin No. 17 procedures were

adjusted slightly to more appropriately fit the San Juan study area.

Results from the agreed upon study procedures varied from those in the

Colorado Water Conservation Board's "Technical Manual No. I." The

variances are reconciled in that the data presented in Manual No.1 is

for generalized use and is not intended to replace detailed analyses In

loca 1 i zed areas.

There are no streamgages located on the McCabe Creek segment'of the

study. Since the characteristics of this drainage are significantly

different from the San Juan River. synthetic hydrograph procedures were

used to develop peak discharge values. The procedures are described in

c - 4

C - 3