WMOD00268

• Applicant: CWCB
• Sponsor Name: USBR
• Project Name: Final Report Weather Damage Mitigation Program
• Title: Numerical Simulations of Snowpack Augmentation for Drought Mitigation Studies in the Colorado Rocky Mountains
• Prepared For: USBR - WDMP
• Prepared By: Curt Hartzell, Dr. William Cotton, Joe Busto
• Date: 9/1/2005
• State: CO
• Weather Modification - Doc Type: Scientific Study

seeding opportunities, but the observed precipitation for this period was slightly
below the long-term average. The first half of March 2004 only had two short
cloud-seeding opportunities; the last cloud-seeding activity ended on March lS,
2004. Warmer than normal temperatures during March resulted in a decrease in
snowpack snow water equivalent (SWE) and some snowmelt runoff at elevations
below about9,SOO-10,000 ft. MSL.

The precipitation trends described above for the first half of Water Year
2004 (October 2003 through March 2004) are evident in Figures 2.3 and 2.4.
These figures show the precipitation and SWE trends for the Natural Resources
Conservation Service (NRCS) SNOTEL sites at Summit Ranch (9,400 ft) and
Fremont Pass (11,400 ft), respectively. Summit Ranch is located on the
headwaters of the Blue River basin on the north side of the OW Program target
area. Fremont Pass is located just outside of the west boundary of the target
area. Overall, for the November 2003 through February 2004 period, the
observed precipitation at the Summit Ranch and Fremont Pass SNOTEL sites
were 98.9% and 87.3% of average, respectively.

The CWCB and OW determined that it was necessary to re-identify the
generator sites not only for the research project, but also for clarity with past and
future operational cloud seeding programs. Greg Bryant (Denver Water GIS
Coordinator) and Joe Busto (CWCB) worked with Larry Hjermstad (WWC) to re-
identify ice nuclei generator sites from initials of the generator operators to a
letter-numbering system. The new site identification (10) consists of a letter
representing the project followed by a number (see Appendix 1). The result was
an Excel spreadsheet that contains the site '0, location, elevation, status, and
olher information for al/ generator sites. This became the official identification
system for OW and CWCB; the new Seeding generator site 10 scheme was built
into the Colorado WDMP research project's GIS and graphics.

During the January 14, 2004 project conference call there was discussion
about using the Generator Site Excel Spreadsheet for WWC seeding reports
(e.g. dates, times, total hours, seeding rates, and primary target areas by site).
Larry Hjermstad (WWC) suggested using one spreadsheet page per cloud-
seeding opportunity event to reduce confusion. This was done and WWC went
back to the start of the OW Program in November 2003 and put all cloud-seeding
event reports into the same format. These event seeding report spreadsheets
were combined into summary spreadsheets at the end of the OW 2003-2004
operational program.

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