Pueblo Mental Health Irrigation Project Final Report

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I I I I I I I I I I I I I I I I I I I SYSTEM RESULTS As previously described in the grant application, the technique for measuring savings as a result of the irrigation automation system, is to predict irrigation usage from the five previous years of data based on the correlation to calculated consumptive use. The historical irrigation usage is identified by first finding the average non-irrigation usage. We used the water meter readings from January, February, and March of each year from 1990 through 1994 to establish the average non-irrigation usage for this time period as shown in Table 1. We then subtracted this average non-irrigation usage from the total water usage during the irrigation period for each of the five years to establish an irrigation total for each month in each year as 'shown in Table 2. It was then necessary to compile the weather data for the time period and calculate the Consumptive Use of irrigation water for each month during the time period. This was done using the Blaney-Criddle method and is shown in Table 3. It was then possible to trend the historical irrigation usage versus the calculated consumptive use of irrigation water and come up with an accurate model for predicting irrigation usage based on weather conditions. This trend information was done in Table 4 and with similar results to the five year period used in the original grant application. The model appears to give results that are within +/- 3 percent for each year of the five year period. Using the model, we then calculated the predicted irrigation usage for 1995 based on weather information and compared it to the actual irrigation usage. Note that the actual irrigation usage was calculated similarly to Table 2 by subtracting the winter average monthly usage. One adjustment was made for a new prison facility that began to be occupied in July of 1995. The San Carlos Correctional facility began filling up in July and is currently up to just over 200 inmates. The water usage in this facility represents a non-irrigation flow that had to be estimated. The results of the savings calculations are shown in Table 5. The calculated savings for the first partial year of operation were 3.76 million gallons of water or about 6.7% of the total irrigation consumption. We feel that these results weren't bad for a partial season and we believe that the system related savings improved towards the end of the period. One factor that was not incorporated in the calculations as an adjustment was the increase in irrigated lawn area since 1993. We have added approximately 10% more irrigated lawn area on campus during this time period and no attempt was made to adjust the model for this additional acreage. The results are encouraging, but will have to be substantiated with a full year of operation. We believe that the expanded system that will be employed for the 1996 irrigation season will help save a significant amount of irrigation water. The irrigation water usage for 1995 was actually down approximately twenty 15