The Denver Elections Commission has announced that the Denver Green Roof Initiative, a mandatory green roof ballot initiative will appear on the November 7 ballot.

A ballot initiative is a means by which a petition signed by a certain minimum number of registered voters can bring about a public vote on a proposed statute or measure.

This is a,

measure that requires every building and any roof replacement of a building with a gross floor area of 25,000 square feet or greater, or a building addition that causes the building to become 25,000 square feet or greater, constructed after January 1, 2018, shall include a green roof or combination green roof and solar energy collection,

With green roof coverage based on the size of the building such that a 25,000 square foot building must have 20% green coverage of available roof space, in increasing area, including that a 200,000 square foot building must have 60% green coverage.

The mandate will require, when structurally possible, the growing media must be a minimum 4 inches. Plant selection is left to the building owner with the requirement that within 3 years of planting, the plants must cover no less than 80% of the vegetated roof. Such a structure will likely be efficacious with respect to storm water management and reducing the roof temperature, but the science of urban heat island effect has been called into question in recent years.

For existing buildings without sufficient loading capacity for a green roof, there will be an exemption process that will encourage implementation of a smaller green roof or some combination with solar panels. Exempted buildings must pay a cash in lieu of construction of a green roof for the reduced or exempted area at $25 per square foot. Violations will be criminal, punishable by a fine of up to $999 and imprisonment for up to one year.

The officially certified content of the ballot was announced in a Tweet from ‎@DenverElections and included Initiated Ordinance 300 – Denver Green Roof Initiative.

A coterie of groups, including Green Roofs for Healthy Cities, announced that they had gathered more than 7,000 signatures of which 4,771 were confirmed valid, just exceeding the 4,726 signature threshold to be included on the ballot by 45 signers.

“More than 80% of the people we talked to loved the idea and wondered why we weren’t already doing it,” according to Brandon Rietheimer, founder of the Denver Green Roof Initiative.

This is believed to be the first successful voter initiative petitioning a green roof mandate to voter ballot.

The proposed green roof requirement is based largely on the City of Toronto Green Roof Law but would apply to not only new, but also expanded existing buildings with over 25,000 square feet.

San Francisco was the first local jurisdiction and one of very few in the U.S. to mandate green roofs or solar panels on new buildings as of January 1, 2017.

In a nation sharply divided about the direction of environmental policy, an environmental initiative petitioned to the ballot by voters is huge. Colorado is has been a Blue state in the last two elections, but Denver is solidly left of center, so it is possible this ballot initiative could pass on November 7.

Environmental voter initiatives could become de rigueur across the country.