Spokane Municipal Code

Title 17D City-wide Standards

Chapter 17D.060 Stormwater Facilities

Section 17D.060.150 Natural Location of Drainage Systems Requirements

1. The proponent of any development project is responsible for reviewing any applicable City or County maps relating to the natural location of drainage systems prior to submitting an application for proposed development review.
    
2. The natural location of drainage systems shall be reserved for the conveyance and/or disposal of stormwater flows. The width of the natural channels and swales shall be determined based on an analysis of the stormwater flows directed to these drainage systems and access and maintenance requirements as stated in the standards as identified in SMC 17D.060.030. The analysis is to be performed by the developer’s engineer for review and acceptance by City.
    
3. All new developments containing tracts one acre or smaller in size shall be designed so that the natural location of drainage systems remain as open space in a separate tract. The developer shall designate ownership of the drainage tract as specified in the current standards as identified in SMC 17D.060.030.
    
4. No cuts or fill will be allowed in a natural location of drainage systems except for driveway or road crossings with approved drainage plan showing engineered culverts or bridges, designed to allow stormwater runoff to pass or to be discharged in accordance with the standards as identified in SMC 17D.060.030 or as described in subsection (I) of this section.
    
5. The natural location of drainage systems shall remain and/or be restored to as natural a condition as possible but may include passive recreation alternatives such as bicycle or hiking trails, provided said uses do not obstruct the function of the drainage system.
    
6. Upon review and approval by the director, drainage ways in a non-residential development and in a residential development containing lots one acre or smaller may be realigned within the development provided that the drainage way will enter and exit the site at the pre-developed location and that discharge will occur in the same manner as prior to development.
    
7. The developer, property owner, or a designated entity acceptable to the City (i.e., homeowners association) shall be responsible for maintaining the natural location of drainage systems unless the City of Spokane, at its option, chooses to maintain the systems as recommended by a comprehensive drainage plan. The developer shall provide a perpetual maintenance plan, including a funding mechanism, for the natural location of drainage systems acceptable to the director of engineering services, in consultation with the director of wastewater management.
    
8. In areas where the natural location of drainage systems coincide with flood zones identified on the Spokane County flood zone maps or the city’s most recent Federal Emergency Management Agency (FEMA) maps, all land division and building permit activity shall meet the requirements of this chapter. In the event of a conflict between the information shown on the published maps and information gathered from field investigations, the latter shall prevail.
    
9. No building permits shall be issued for structures, including manufactured homes, located in the natural location of drainage systems other than utility structures and ancillary buildings or structures associated with the passive recreational alternatives as set forth in subsection (E) of this section that can be constructed without obstructing the function of the drainage system.

Date Passed: Monday, March 8, 2010

Effective Date: Sunday, April 11, 2010

ORD C34564 Section 14