Big Thompson River
FISH SURVEY AND MANAGEMENT DATA
Benjamin Swigle - Aquatic Biologist (Fort Collins/Boulder)
[email protected] / 970-472-4364
General Information: The Big Thompson River below Olympus Dam is a famous trout river which attracts
thousands of anglers each year. Fishing for brown and rainbow trout can be good to great almost year round.
Fishing within the catch and release section (Watonia bridge to Olympus Dame) will produce good
numbers. A s a result of the flood, angling below Drake will be poor in 2014.
Location: From Loveland, follow Highway 34 west to the Big Thompson Canyon approximately 10-30
miles west of Highway 287.
Fishery Management: Coldwater angling
Purchase a Fishing License: https://www.co.wildlifelicense.com/start.php
Amenities
Limited number of access
points along HWY 34 as crew
continue to restore both the
river and the road post flood.
Sportfishing Notes
Trout
Fishing a dry-and-dropper
setup is a great initial
approach for both browns and
rainbows. Fishing small
streamers is a good option as
well.
Previous Stocking
NONE: trout reproduce
naturally in the Big Thompson.
available
below Olympus dam.
Young of year brown trout
typically emerge from the nest
in May while rainbows emerge
during June.
Regulations
From Olympus Dam (east end
Estes Lake) to Waltonia Bridge
requires a fly or lure for catch
and release fishing.
Solid numbers of rainbow and
brown trout were identified post
flood upstream of Drake. These
populations will serve as the
primary source to naturally
repopulate sections of river as
restoration work is completed in
the coming years.
Primitive restroom
The rest
Nymphs:
Z-wing caddis (#16),
Mangy caddis.
Dry flies:
Hatchmasters (#18)
Terrestrials:
beetles (#16), ants
(#18)
Rather than restocking,
preference remains that the Big
Thompson be re-populated by
wild strain rainbow and brown
trout.
of the Big Thompson
River below Waltonia isopen
fishing (general regulations
apply). Please use extreme
caught as construction crews
remain in the area.
Respect
private property
boundaries as posted.
Big Thompson River – Below Olympus Dam
Graph 1: The estimated number of 6-inch plus rainbow and brown trout per mile based on multi-year sampling at the
Olympus station. Abundance for rainbow trout has increased post flood; a flushing effect of fish moving out of Lake
Estes. Brown trout has abundance has remained steady over the past decade. A vast, vegetated flood-plain below the dam
absorbed the flood waters and remains essentially unaltered.
3500
Graph 1.
Rainbow Trout
Estimated # Trout (>6") per mile
Gear: Electrofish 2 pass, 10/2013
Station: Olympus
Length: 367 ft (between arrows)
X Width: 35.8 ft.
Est. # Trout (6”+) per mile: 4,212
3000
Brown Trout
2500
2000
1500
1000
500
0
2002
2003
2004
2005
2008
2009
2011
Survey Summary Below Olympus Dam 10/30/2013
Total
Mean
Minimum
Sampled inches
lbs
inches
lbs
6
8.8
0.25
6.0
0.06
92
11.9
0.64
5.9
0.12
199
11.0
0.50
8.1
0.18
1
12.9
0.69
12.9
0.69
SPECIES
BROOK TROUT
BROWN TROUT
RAINBOW TROUT
SPLAKE
2013
Maximum
inches
lbs
10.6
0.38
16.2
1.49
15.2
1.29
12.9
0.69
Total
Weight
sample
Lb
Number
Weight
Lb/Acre
Num/Mile
BROOK TROUT
6
1.5
2.0
0.9
4.3
86.3
BROWN TROUT
92
59.8
30.9
36.7
172.6
1,334.2
RAINBOW TROUT
199
100.9
66.7
62.0
291.4
2,878.3
1
0.7
0.3
0.4
2.0
14.4
Species
SPLAKE
Percent
Biomass
Google Earth
Big Thompson River below Olympus Dam:
September 2013
Big Thompson River below Olympus Dam:
11/07/2013
Vegetated Banks (willows), a broad flood-plain, correct sinuosity allowed this
section to remain unharmed by flooding.
Parking Area
Big Thompson River – Handicap Fishing Pier
Graph 2: The estimated number of 6-inch plus rainbow and brown trout per mile based on multi-year sampling at this station.
Abundance of brown trout at this site has increased to a 10 year peak of an estimated 1,523 browns per mile as estimated post flood.
Rainbow numbers fell compared from 2009 but remain solid. Again, these are post flood estimates.
3000
Estimated # Trout (>6") per mile
Gear: Electrofish 2 pass, 11/17/13
Station: Handicap Ramp
Length: 170 ft (between arrows)
X Width: 29.8 ft.
Est. # Trout (6”+) per mile: 3,451
Graph 2.
Rainbow Trout
2500
Brown Trout
2000
1500
1000
500
0
2002
2004
2005
2006
2008
2009
2011
2013
Stream Sampling Summary Report - Big Thompson @ Handicap Pier
Total
Sampled
SPECIES
Mean
inches
lbs
Minimum
inches
lbs
Maximum
inches
lbs
BROWN TROUT
58
10.16
0.36
4.72
0.04
14.57
0.84
RAINBOW TROUT
46
9.72
0.30
7.87
0.15
12.68
0.49
Total
Weight
sample
Lb
Number
BROWN TROUT
58
20.7
55.8
59.7
152.3
428.6
1,927.7
RAINBOW TROUT
46
14.0
44.1
40.2
102.7
338.6
1,522.9
Species
Percent
Biomass
Weight Lb/Acre
Num/ Acre Num/Mile
Big Thompson River – Upstream of former Idlewilde Dam
4000
Brown Trout
3500
#Trout >6" per mile
Rainbow Trout
3000
2500
2000
1500
1000
500
0
2012
2013 (post flood)
The station downstream of the Handicap Fishing pier, sampled in both 2012 and post-flood 2013, yielded 80% less fish
following the flood. This section of stream is located just upstream of the Idlewilde Dam which was removed this spring.
Removal of the dam will eventually benefit trout in the Big Thompson because a significant passage barrier has been
removed along with sediments which often times harbor parasites responsible for whirling disease.
Rainbow Trout (2.6– 14.8”)
Brown Trout (3.7–14.0”)
Big Thompson River – Viestenz/Smith Mountain Park
Table below: The estimated number of 6-inch plus rainbow and brown trout per mile based on two years of sampling at this
location (Fall 2012 and post Flood 2013) within the Viestenz-Smith Mountain Park. The park was maintained by the City
of Loveland and was the site of their hydro-electric facility. Abundance of brown and rainbow trout has drastically
decreased. Post flood work that temporarily channelize the river, removed large boulders, and relocated all woody debris
has left this site incapable of sustaining large numbers of trout. Restoration work by a large contingent of agencies will
eventually transform this reach back to its former glory.
SPECIES
LONGNOSE SUCKER
BROWN TROUT
RAINBOW TROUT
Stream Sampling Summary @ Viestenz/Smith (9/27/2012)
Total
Mean
Minimum
Sampled
inches
lbs
inches
lbs
5
12.3
0.86
11.3
0.61
176
9.8
0.40
6.3
0.08
27
10.6
0.50
6.5
0.12
Total
sample
5
13
176
27
Species
LONGNOSE SUCKER
LONGNOSE DACE
BROWN TROUT
RAINBOW TROUT
SPECIES
BROWN TROUT
RAINBOW TROUT
Species
BROWN TROUT
RAINBOW TROUT
Weight
Lb
0.77
0.00
0.19
0.12
Percent
Number
Weight
1.9
1.9
4.8
0.01
65.2
0.5
10.0
0.3
Maximum
inches
14.4
19.9
14.5
Biomass
Lb/Acre
1.71
0.01
0.42
0.26
Num/ Acre
11.0
28.7
388.9
59.6
lbs
1.40
2.22
0.97
Num/Mile
58.9
153.2
2,074.2
318.2
Stream Sampling Summary @ Viestenz/Smith Post Flood (11/27/2013)
Total
Sampled
13
inches
10.92
4
7.95
Total
sample
13
4
Mean
Weight
Lb
0.36
0.21
lbs
0.48
inches
7.48
0.20
6.81
Minimum
Percent
Number
Weight
76.4
11.2
23.5
6.6
Maximum
inches
lbs
15.16
1.18
lbs
0.15
0.11
8.94
Biomass
Lb/Acre
0.98
0.59
0.23
Num/ Acre
Num/Mile
35.6
168.2
10.9
51.8
Sections of the Big Thompson that have been temporarily
channelized maintain very few trout. Restoration efforts by a
number of agencies is underway, but the take home message
for anglers is to fish further upstream in the Big Thompson
drainage and away from sections immediately adjacent to HWY
34.
For more information on restoration events and how to
contribute to the recovery visit: http://bigthompsonriver.org/