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Stormwater Management

The City of Lone Tree is the primary manager of stormwater in the City.

As an integral part of Lone Tree’s vision of providing its citizens with the highest quality services at the best value with respect to stormwater management, the City will, to the maximum extent practicable:

  • Safeguard the public welfare through the proper collection, conveyance and storage of stormwater runoff in a non-damaging and non-life threatening manner.
  • Ensure compliance with all applicable water quality regulations related to stormwater runoff, including and in particular, both the WQCD’s Stormwater Phase II Program and the Cherry Creek Reservoir Control Regulations, respectively.
  • Ensure that all City stormwater facilities are functioning and well maintained, including applicable open channels (i.e., stable physical characteristics).
  • Ensure sound management and regulation of City floodplains, particularly with respect to Federal Emergency Management Agency requirements.
  • Protect the overall water quality of the City’s water resources. This includes implementation and enforcement of the applicable Grading, Sedimentation and Erosion Control standards to control runoff from construction sites (both residential and commercial) within the City.
  • Provide healthy and diverse natural habitats for flora and fauna in applicable drainage ways and City open spaces.
  • Integrate recreational opportunities and facilities into drainage way planning, where feasible.

Municipal Separate Storm Sewer System (MS4) Management Program

The City has been granted a permit from the Colorado Department of Health and Environment (CDPHE) allowing the City to discharge water from the City’s stormwater system in accordance with pollutant restrictions, prohibitions, and reduction requirements and monitoring requirements and other conditions.

The City’s 2016-2021 MS4 permit can be viewed here.

City of Lone Tree MS4 Annual Reports

Federal and State Regulations

The U.S. Environmental Protection Agency (EPA), as part of the National Pollutant Discharge Elimination Systems (NPDES) Program, has passed regulations and requirements for managing potential contamination of stormwater. Within Colorado, the Colorado Department of Public Health and Environment (CDPHE) has developed regulations for implementing and complying with these Federal Stormwater requirements.  These State requirements are managed through the Water Quality Control Division of the CDPHE. The City is responsible for stormwater control within the city limits and is required to comply with the requirements of the associated Stormwater NPDES Permit (MS4) that is administered through the CDPHE.

Stormwater Phase II Permittee

Under the EPA and CDPHE Stormwater Phase II Program, the City of Lone Tree is a Stormwater Phase II permittee under the State General Stormwater NPDES General Permit COR0800000 and the City-specific Permit COR-080016. The first version of this Permit became effective March 2003, and as such, the City of Lone Tree has taken the lead role in stormwater and drainage way management within the City. This includes coordination with respect to additional requirements for development in those areas within the City which are tributary to the Cherry Creek watershed basin.

Cherry Creek Basin within Lone Tree

Portions of the City of Lone Tree are within the Cherry Creek Basin watershed. Stormwater within those areas ultimately drain into the Cherry Creek system and are tributary to the Cherry Creek Reservoir. The City’s Stormwater General Permit contains requirements associated with protecting water quality within the Cherry Creek watershed and the Cherry Creek Reservoir.

The Cherry Creek Water Quality Basin Authority (CCWQBA) was established by the state legislature to lead the Cherry Creek Basin protection efforts. The legislature granted the CCWQBA authority to assess certain rates/fees/charges to assist in that program. In conformance with an Inter-governmental Agreement between the City of Lone Tree and the CCWQBA, the applicable CCWQBA fees on new development in the Cherry Creek Basin within the City of Lone Tree are collected by the City, through the City Building Department, and are submitted by the City to the CCWQBA.