CWCB San Miguel PHS Final

• Case Number: 11CW0129
• Stream Name: San Miguel River
• Watershed: San Miguel
• Water Division: 4
• Water District: 60
• County: Montrose
• Instream Flow App - Doc Type: ISF INV - Hearing

• 325 cubic feet per second is required to maintain a reasonable amount of bluehead and
flannelmouth sucker usable spring and summer habitat, in addition to maintaining the
three principal hydraulic criteria of average depth, average velocity and percent wetted
perimeter at adequate levels;
• 115 cubic feet per second is required to maintain a reasonable amount of bluehead and
flannelmouth sucker usable fall and winter habitat, in addition to maintaining two of the
three principal hydraulic criteria.
The recommended flow values were determined using the best professional judgment of CDOW
and BLM biologists and hydrologists. The CDOW and BLM professionals reviewed and
evaluated the results of the Physical Habitat Simulation ( PHABSIM) Methodology and
RHABSIM software PHABSIM/RHABSIM analysis. They also reviewed the R2CROSS
analysis, using standard hydraulic criteria.
Land Status Review
Upper Terminus
Lower Terminus
Total Length
(miles)
Land Ownership
% Private
% Public
CALAMITY DRAW
TABAUCHE CREEK
10.0
85%
15%
TABAUCHE CREEK
DOLORES RIVER
6.5
52%
48%
28% of the public lands are managed by the BLM.
Biological Data
Over the past ten years, the CDOW and BLM have been collecting stream cross - section
information, natural environment data, and other data needed to quantify the instream flow needs
for this reach of the San Miguel River. The San Miguel River is classified as a large river (over
100 feet wide) and fishery surveys in 2001 indicate the stream environment supports: bluehead
sucker (Catostomus discobolus), flannelmouth sucker Catostomus latipinnis, mottled sculpin
(Cottus bairdi), roundtail chub (Gila robusta), speckled dace (Rhinichthys osculus) and white
sucker (Catostomus commersoni) (See CDOW Fish Survey in Appendix C).
In addition, the BLM has been collecting aquatic invertebrate samples, for several years, at
several sites within the proposed instream flow reaches. These sites include the San Miguel
upstream of the Dolores, at Tabequache Creek and upstream of Tabequache Creek (see
Appendix D).
Biological and Field Survey Data
The CDOW and BLM collected transect and flow data for 7 different cross - sections within an
815 foot reach of stream. The transect data was collected at a site approximately 1.5 miles
upstream from the confluence of the San Miguel River with Tabeguache Creek. These 7
transects incorporated different mesohabitat types including riffles, runs, pools and glides. These
7 different cross - sections formed the basis for the PHABSIM/RHABSIM study conducted by the
CDOW and BLM. PHABSIM is widely used in North America to quantify instream flow
I