DWR_2669034

• Title: STREAM FLOW DATA FOR COLORADO
• Year: 2010
• Document Type - Publications and Reports: Streamflow Report

Discharge.--
PLATTE RIVER BASIN
TARRYALL CREEK AT BORDEN DITCH
Location.--
Drainage and Period of Record.--
Lat. 39º17’13”,Long. 105º41’43”, in the NW ¼ of the NW ¼ of Sec. 8, T. 9 S., R. 74 W., Park County, Hydrologic unit
10190001, on left bank 1800 ft. downstream from Rock Creek, 9 mi. southeast of Jefferson and 1.0 mi. northwest of
Bordenville.
230 mi². Apr. 26, 1983 (no previous gage at this site). Operation discontinued by USGS Sept 30, 1997. Taken
over by Colorado Division of Water Resources.
Sutron SatLink 2 satellite monitoring data collection platform (DCP) with a Sutron 56-0540 shaft encoder (SE) enclosed in a
steel box shelter atop a 18 inch corrugated metal pipe (CMP) mounted vertically on the stream bank. Well has a clean-out
door on the stream side. The primary gage reference is a drop tape with shelf mounted reference point (RP). There is a
supplementary outside staff gage. The gage and satellite monitoring equipment are owned and maintained by the City of
Aurora. Aurora operates the gage seasonally and it is shut down in the winter. Colorado Division of Water Resources
(DWR) operates the gage under a contract with City of Aurora to provide real time data and for record development.
Equipment.--
Hydrologic Conditions.--
Gage-Height Record.--
Datum Corrections.--
Rating.--
Discharge.--
Special Computations.--
Remarks.--
Recommendations.--
High mountain alluvial plateau mostly devoid of forest. Conditions remain stable with continued light residential
development upstream. Discharge affected by irrigation diversions, releases from Jefferson Lake and James Tingle
reservoir.
Primary record is hourly averages of telemetered 15-minute satellite data. The record is complete and reliable except as
follows. October 19, 2009 and April 21, 2010: incomplete data, estimated record (shut-down for winter and start-up days).
October 20, 2009 through April 20, 2010: station off for winter, no record maintained. Instrument calibration was verified by
twenty one visits made to the gage. Two SE adjustments were made (0.01 and 0.02 ft.).
Levels were run on August 12, 2010 to the reference point (RP) using Reference Mark No. 1 (RM1) as base. Levels
revealed the RP elevation was 0.02 feet lower than found last year. The gage is susceptible to movement following harsh
winters experienced in this area. It is assumed the gage had shifted following winter. As such, a datum correction of -0.02
feet was applied from the spring startup of April 21 to August 16, 2010 when the first measurement was made following
levels. Rather than adjusting the RP, it was relocated and re-indexed to an elevation of 9.915 feet. Relocation of the RP
was critical to resolve difficulties associated with reading the RP in its previous configuration. The metal tape length was
then adjusted to 9.915 ft. RM1 - 7.034 feet ,RM3 - 8.505 feet, RM2 - Elevation for RM2 abandoned (9/28/2009).
The control at low to medium flows is a rock riffle downstream composed of gravel, sand and some large boulders. The
stream channel is the control for higher stages up to an approximate gage-height of 6.00 ft where the channel is subject to
overflow. The gage is approximately 100 ft. upstream. Rating No. 6 was used all year and is well defined between 1.11
and 247 cfs. It is valid for the range of flows experienced this year. Ten measurements were made (Nos. 80 - 89), ranging
in discharge from 17.5 to 208 cfs. Average daily flow was above the highest measurement on the following days: June 12-
15, 2010. The peak discharge of 304 cfs occurred at 1315 on June 13, 2010 at a gage height of 4.10 ft. with a shift of 0.05
ft. and a datum correction from levels of -0.02 ft. It exceeded measurement No. 83 by 0.53 ft. in stage and 96 cfs
respectively.
Shifting control method was used all year. Shifts were applied as defined by measurements and were distributed mainly by
time with some consideration to change in stage. Unadjusted shifts ranged from 0.00 to 0.06 feet. Measurement No. 87
was adjusted by 2 % to better match adjacent shifts. Shifting is caused by the movement of material (sand, silt, rocks, and
boulders) across the control and gage pool sections. The range in stage experienced this year was confined to the channel.
Frost heave can affect the first measurements of the spring, since the creek thaws before the ground. Shifts were applied
as follows. October 1-19, 2009: stage shift table TARBORCO VST2 from WY 2009 defined by measurements Nos. 73-80.
April 21 through September 30, 2010: time proration applied as defined by measurements and distributed mainly by time
with some consideration to change in stage. Shifts for Msmt. Nos. 83 and 86 held to peak events. This is a partial year
record. No discharge record is kept for the winter period.
Discharge from Tarryall Cr. bl. Tarryall Reservoir gage used to help assess for possible ice effect at this gage during
October 2009.
The record is rated good, except for the start up and shut down days of October 19, 2009 and April 21, 2010 which were
estimated and are considered poor. No estimates were made for the winter period from October 20, 2009 through April 20,
2010 as the gage is considered seasonal. Station maintained and record developed by Mike Wild.
Gage shelter should be replaced. Access to the gage will be improved during construction to County Road 77 scheduled
for summer 2011 allowing gage work to proceed in the fall.
2010Water Year