Primary indicators for infrastructure systems consist of measures such as these:
- Greenhouse gas emitted per ton of solid waste managed.
- Greenhouse gas emitted per cubic meter of wastewater treated.
- Percent of green (renewable) power purchased by the city or county.
Primary indicators directly measure progress towards the end goal or goals, such as greenhouse gas emissions. While they provide clear evidence of progress, they often require collection of data from many places, so they can be difficult to measure regularly.
Such indicators give municipalities a sense of where they can act to improve infrastructure performance.
It’s important to remember that indicators only show selected information. For instance, tracking greenhouse gas per cubic meter of water treated accounts for emissions only from operation of the water treatment facility operation, not from its construction or eventual decommissioning.
Greenhouse gas emissions are calculated using estimated factors, which may not always accurately represent a system’s total emissions.
Secondary Indicators include measures of downstream activities. That focus can help reveal progress toward the goals. For example:
- Is there an energy manager or an energy commission?
- Do alternative design standards allow narrow roads, which free rights-of-way to help absorb stormwater and keep it out of treatment facilities?
- Do regulations support development of trails & swales?
Secondary indicators measure progress indirectly, through measurable physical characteristics that are closely linked to achievement of the end goal or goals, such as average residential density.
