Stormwater Quality in Mountlake Terrace

Surface water drainage in Mountlake Terrace is greatly influenced by the urbanized nature of our community as well as that of our surrounding communities. The Hall Creek - Lake Ballinger drainage basin collects stormwater runoff from Mountlake Terrace as well as the cities of Lynnwood, Edmonds and Shoreline. All these areas have experienced expansion of impervious areas with increased development. More impervious areas such as streets, parking lots, and building roofs have led to increased runoff to surface streams and lakes. This increased runoff also carries with it pollutants picked up from streets, lawns, construction sites and commercial properties. Common water quality problems that can occur as a result of surface water runoff include depleted dissolved oxygen levels, increased water temperature and sedimentation. The presence of excess nutrients, fecal matter, hydrocarbons, heavy metals and pesticides are also things that can negatively affect water quality.

The City of Mountlake Terrace has implemented a number of measures to help minimize and reduce the impact of urban runoff pollutants in our surface streams and lakes. All new development and redevelopment projects must meet state standards for stormwater runoff during the construction portion of the project. Post development runoff must also meet state standards for runoff quantity and quality through the use of detention ponds and vaults, water quality filters and grass lined swale or soil infiltration trenches. In 2007 and 2008, the City implemented a program to actively filter stormwater pollutants from selected areas of the City that are tributary to Hall Creek and Lake Ballinger.

Illicit Discharge & Spill Control

Spill Control Hotline - To report a spill or discharge of any contaminants to the stormwater system call the Public Works Department at 425-744-8264 between 8 a.m. and 4 p.m. weekdays. Call 911 after hours or on weekends or holidays. A staff member will investigate the issue to minimize the entry of contaminants into the City stormwater system.
Litter in Sewer Drain

What You Can Do

While these practices can help keep surface water clean there are some simple things you can do to help ensure that our streams remain healthy such as:
  • Clean up after your pet by using a pet waste disposal station or garbage can.
  • Consider natural methods of pest control and if pesticides must be used, use them sparingly.
  • Maintain stream buffers by protecting shrubs, vines and other plants along streams.
  • Use fertilizers sparingly on lawns and gardens, and use natural organic fertilizers. Consider using natural and organic methods of lawn care.
  • Keep toxins, such as engine oils, paint thinners, and pesticides out of stormwater drains and dispose of them safely at a household hazardous waste collection site.