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Texas AgriLife Extension Service Texas Water Development Board Texas Nursery and Landscape Association Texas AgriLife Extension Service Texas AgriLife Extension Service
A supplement to the Best Management Practices Manual produced by the Texas Water Conservation Task Force.


The Best Management Practices Guide has specific recommendations for program implementation and tracking. Those concepts are not repeated in this section. Rather, this includes some information, gathered from input of landscape conservation professionals from different utilities, about potential program elements to consider based upon the size of a utility. Utilities should be considered as small if less than 3,300 to 49,999 connections, as medium with 50,000 to 99,999 connections, and as large with 100,000 connections or more. Some very small utilities, those with less than 3,300 connections, have implemented educational programs in using educational brochures and bill stuffers.

Cost Effectiveness Considerations
Using the cost-effectiveness model presented with the Best Management Practices Guide (p.122-126), the utility will need to obtain certain data and make some assumptions about its goals for the program.

Customer billing data can give a clue to the number of customers that have a pattern of large increases in water use in summer months. These indicate a high potential for irrigated landscapes, although some commercial customers may be using large quantities of cooling water in the summer months.

The number of probable landscape irrigators should be determined and an amount of water savings in gallons per customer per day per measure must be estimated. The model in the Guide indicates a savings rate of 50 qpd for irrigation surveys for customers and 470 qpd for commercial customers. Values for landscape conversion programs show in the range of 100 qpd for El Paso, although other programs have not been as consistent. Water savings estimates for landscape education programs are not available. 

A program penetration goal needs to be determined, which is multiplied times the total estimated customers who irrigate to determine both the number of surveys or conversions the program will strive to perform, and is used to estimate the cost and potential water savings of the program. The length of the proposed program will need to be entered, and the estimated life of the measure.

The irrigation survey program has a natural replacement rate of zero because experience and discussions with professionals have determined that few, if any, customers seek out irrigation surveys without a utility sponsored program. However it includes a 1% free ridership value to account for some customers who will access the program to help them fix a problem of which they are already aware.

Net program costs for the irrigation survey in 2004 are estimated at $51 per residential survey and $202 per commercial survey. These values should be increased for inflation and can be adjusted in the model to reflect a utility’s actual costs. Such costs could be based upon the value of utility staff time to perform an irrigation system evaluation or the cost of a rebate to provide an incentive for customers to use a landscape professional to perform the service.

Based upon the values entered, the model calculates the cost of water per AF saved, the total cost of the program, the net present value of water saved per AF, and the estimated water saved over the life of the measure. The values of these variables can be used to determine the value of the proposed program, how large or for how long a program should be designed and operated. The final values will be dependent both upon customer data, and upon the assumptions the planner uses in the model which can be adjusted.

"Landscape planning and design is essential to water use efficiency..."

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