The CaDC Efficiency Explorer is a planning and education tool for local water managers and the wider California water community. This tool is the result of a rapid first assessment of Governor Brown's Executive Order B-37-16, which calls for the development of water use efficiency goals customized to the unique conditions of each urban water agency as part of a new, permanent efficiency framework.
For version one of the Efficiency Explorer, the CaDC focused on the residential component of an agency's efficiency efficiency goal. This goal is calculated as the sum of indoor and outdoor residential water use budgets, and can vary according to unique agency conditions as well as pending policy decisions.
The parameters of these two budgets are displayed in the labeled panels above. Click each parameter for descriptions, data sources, and data quality considerations for this iteration of the CaDC Efficiency Explorer.
Since data quality is an important dimension for this rapid first assessment, data quality flags are included for each agency. These flags are explained in the Data Quality section below. For additional technical details, please see the CaDC Statewide Efficiency Explorer Methodology Documentation.
For all other questions and feedback, users are encouraged to reach out to info@CaliforniaDataCollaborative.com!
There are two distinct senses in which efficiency goal calculations can deviate from ground truth: precision and accuracy.
Parameter data used to calculate efficiency goals can be imprecise. Imprecision reflects deviations around a true value. The Efficiency Explorer's graphs include gray confidence bands around each agency's calculated goal to indicate the imprecision resulting from the compounded statistical error for all parameter data sources. Analogous to the relationship between the darts and the bullseye in figure (a) above, one should expect the ground truth efficiency goal values to lie somewhere within the confidence bands (for agencies not flagged as showing evidence of systematic inaccuracy). For technical details on each component error source, please see our error model. One key result from this error analysis is the break down of the aggregate goal error by budget: indoor budgets are expected to lie within approximately 3% of their estimates, while outdoor budgets are within 40%. Takeaway: while imprecise efficiency goal calculations can be further refined, they are useful first approximations of ground truth.
As alluded to above, in certain situations parameter data used to calculate efficiency goals can be not only imprecise, but also inaccurate. Inaccuracy reflects a more systematic bias away from ground truth. Figure (b) above graphically illustrates this type of error. Non-random inaccuracies can arise from situations such as the prevalence of large rural residential parcels in certain districts, which would result in systematic overestimation of goal calculations in those districts. The prevalence of brown lawns in other districts would result in systematic underestimation of goal calculations in those districts. Roughly 20% of agency efficiency goal calculations show evidence of this more problematic source of error. The component data inaccuracies are broken down in a CaDC data quality blog post. Takeaway: efficiency goals flagged as systematically inaccurate should not be interpreted as useful approximations and have been grayed out on the map.
By setting values for GPCD and ET Adjustment Factor, users can investigate how different standards for residential water use affect their agencies over different periods of time.
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Residential Efficiency Goal: