WMOD00274 ‎(2)‎

• Title: Hydro-Climate Index Study - Final Report
• Prepared By: HDR Engineering
• Date: 2/14/2008
• County: Statewide
• State: CO
• Weather Modification - Doc Type: Report

Table 2. Summary of Apr.-Jun. Precipitation/HCI Relationships (‘X’ indicates a relatively strong
relationship and ’O’ indicates a relatively weak relationship).
PDOMEISOINino 3.4 NAOAMO
District 26
O
District 20 OO
District 35
OO
C -Summer Precipitation (July-September) – Single Seasonal Totals
Districts 26, 20 and 35
Unfortunately, little useful information was gleaned from this segment of
information as the connections between the HCI variables and all three districts were
minimal, at best. This factor may show that even in dry years these basins may have some
average precipitation production to help overcome water shortages.
D - Summer Precipitation – Days with 0.10” or greater (May 1-September 15)
Due to data requirements to analyze this variable only two stations in the basin
(Alamosa and Great Sand Dunes) met this requirement. An analysis of the values
indicates a minimal useful ‘connection at Great Sand Dunes, on the east side of the
valley. However, at Alamosa there was some relationship with the AMO with negative
values correlating somewhat well with average/above average days with 0.10” of
precipitation or greater and vice versa for negative AMO values. Given the lack of
stations to analyze with this data, some caution is offered to using this data as a potential
‘planning’ tool rather than information of note.
E – Naturalized Stream flow Volume (April – September)
One of the most important factors in the hydrologic cycle that is observed in the
state of Colorado is surface water. This section will briefly outline the ‘resulting’ factor
of winter snows and spring precipitation and how directly calculated naturalized runoff
might be influenced by the HCI variables. Also the temporal aspect of ‘how’ runoff
might be influenced by the HCI variables will be discussed.
District 26
The overall stream flow correlations exhibit some interesting connections in the
area but one that is most notable is the AMO where negative values tend towards positive
values of stream flow. Also of note is the lack of excessively dry years as well with
Figure 7
negative compared to positive years (). Secondary, but weaker index values that
correlate to stream flow include the ENSO (SOI/MEI) variables as well.
14