ORDINANCE No. 176783

Amend Chapter 17.38 and Chapter 24.10 to revise stormwater management requirements for consistency with the City Stormwater Management Manual. (Ordinance; amend Chapter 17.38 and Chapter 24.10)

The City of Portland ordains:

Section 1.  The Council finds:

1.  The Bureau of Environmental Services has completed the biennial, 2002 revision of the City's Stormwater Management Manual.

2.  Comments from the Stormwater Advisory Committee, other public stakeholders and City staff directed that the 2000 Stormwater Management Manual be simplified and re-formatted for clarity. The 2002 Stormwater Management Manual revision is to become effective on September 1, 2002.

3.  Amendments to Chapter 17.38 and Chapter 24.10 are necessary to modify the stormwater management requirements to reflect changes proposed in the 2002 Stormwater Management Manual.

NOW, THEREFORE, the council directs:

a.  Section 17.38.025 is amended as follows:

B.2.  Land use activities of particular concern as pollution sources shall be required to implement additional Best Management Practices for pollution controls including but not limited to, those management practices specified in the Stormwater Management Manual.

B.3.  Development in a watershed that drains to streams with established Total Maximum Daily Load limitations, as provided under the Federal Clean Water Act, Oregon Law, Administrative Rules and other legal mechanisms shall assure that water quality control facilities meet the requirements for pollutants of concern, as stated in the Stormwater Management Manual.

C.1.  Development shall mitigate all project impervious surfaces through retention and onsite infiltration to the maximum extent practicable. Where onsite retention is not possible, development shall dretain and infiltrate stormwater and detain the surface runoff of stormwater through a combination of provisions that prevent an increased rate of flow leaving a site during a range of storm frequencies as specified in the Stormwater Management Manual or Administrative Rules.

C.2.  The Director may exempt areas of the city from the requirements of 17.38.025.C.1 if flow control is not needed or desirable and if:

a.  Sstormwater is discharged to a large waterbody directly through a private outfall, or

b.  Stormwater is discharged to a waterbody directly or through a separated public storm sewer having adequate capacity to convey the additional flow.

C.4.  Facilities shall be designed to safely conduct convey the less frequent, higher flows through or around facilities without damage.

C.5.  Stormwater quantity discharge which is not practicable to be managed to control quantity as defined in 17.38.025 C.1. through 17.38.025 C.4. and the Stormwater Management Manual; , shall either be managed in an off-site facility or be given the option of paying a stormwater off-site management fee. The Bureau will employ a methodology for calculating the fee that is based upon an average unit cost of on-site facilities where such facilities would be effective. The stormwater off-site management fee collected will be placed in a mitigation account to be used to mitigate the impacts that arise from off-site discharge of stormwater runoff. Information relating to sites that are paying fees will be evaluated in planning for capital improvement projects.

The remainder of this section is unchanged.

b.  Section 17.38.030 is amended as follows:

B.  "Capacity". The capacity of a stormwater system shall mean the flow volume or rate that a facility (e.g., pipe, pond, vault, swale, ditch, drywell, etc.) is designed to safely contain, receive, convey, treat or infiltrate stormwater that meets a specific performance standard. There are different performance standards for treatment, detention, conveyance, and disposal. Example: Public storm sewer pipes are required to convey the 10-year storm without surcharge, and the 25-year storm without damage to property or endangering human life or public health. Public infiltration sumps are required to infiltrate the 10-year storm with a safety factor of two. Combined sewers that overflow during a 25-year storm are not considered to have adequate capacity.

B.C.  "Combination Facilities". Systems that are designed to meet two or more of the multiple objectives of stormwater management.

C.D.  "Director." The Director of the Bureau of Environmental Services, or the Director's designee.

D. "Development." Any human induced change to improved or unimproved real estate, whether public or private, for which a permit is required, including but not limited to construction, installation or expansion of a building or other structure, land division, street construction, drilling, and site alteration such as that due to, dredging, grading, paving, parking or storage facilities excavation, filling or clearing.

D.E.  "Disposal". The ultimate discharge point for the stormwater from a site. Disposal points can include drywells and sumps, soakage trenches, ditches, drainageways, rivers and streams, off-site storm pipes, and off-site combination sewers.

E.F.  "Drainageway". An open linear depression, whether constructed or natural, which functions for the collection and drainage of surface water. It may be permanently or temporarily inundated.

F.G  "Impervious Surface." Any constructed surface that has a runoff coefficient greater than 0.8 (as defined in the Sewer Design Manual, Chart 10 “Runoff Coefficients”). Note: Decks which do not retain water are considered pervious.

H.  "Off-Site Stormwater Facility". Any stormwater management facility located outside the property boundaries of a specific development, but designed to reduce pollutants from and / or control stormwater flows from that development.

I.  "On-Site Stormwater Facility". Any stormwater management facility necessary to control stormwater within an individual development project and located within the project property boundaries.

J.  "Pollutants of Concern." Watershed-specific parameters identified by the Oregon Department of Environmental Quality (DEQ) as having a negative impact on the receiving water body.

G.K.  "Practicable." Available and capable of being done as determined by the Director, after taking into consideration cost, existing technology, and logistics in light of overall project purpose.

H.L.  "Public Works Project." Public Works Project means any development conducted or financed by a local, state, or federal governmental body and includes Local Improvements and Public Improvements as defined in Title 17, PUBLIC IMPROVEMENTS.

I.M.  "Redevelopment." Development that requires demolition or complete removal of existing structures or impervious surfaces at a site and replacement with new development. Maintenance activities such as top-layer grinding and repavement are not considered redevelopment. Interior remodeling projects are also not considered to be redevelopment. Utility trenches in streets are not considered redevelopment unless more than 50% of the street width is removed and re-paved.

N.  "Site Map". For purposes of this code section, a site map shall show the stormwater management facility location in relation to building structures or other permanent monuments on the site. The Sit map shall depict location of sources of runoff entering the facility and the discharge point and type of receiving system for runoff leaving the facility.

J.O.   "Stormwater Management" The overall culmination of techniques used to convey, remove reduce pollutants from, detain, and/or retain, and dispose of stormwater in a manner that to best preserves or mimics the natural hydrologic cycle, to accomplish goals of reducing combined sewer overflows, or to incorporate sustainable building practices by reusing stormwater, on a development site. Stormwater management shall be implemented in a manner that protects pPublic health and safety, aesthetics, maintainability, capacity of the existing infrastructure and sustainability are important characteristics of a site’s stormwater management plan. and fits within the capacity of existing infrastructure on a development site and the approved receiving system(s) for stormwater runoff

P.  "Stormwater Management Facility". A single technique used to treat, detain, and/or retain stormwater to best preserve or mimic the natural hydrologic cycle, or to fit within the capacity of existing infrastructure, on a development site..

Q.  "Tract". A tract is a section of land set aside from development during the Land Division phase of development. Tract as used in this code section shall be the definition of tract as described in Title 33 of the City Code.

K.R.  "Water Body." Rivers, streams, sloughs, drainages including intermittent streams and seeps, and ponds, lakes, aquifers, wetlands, and coastal waters.

L.S.  "Watercourse." Watercourse means a channel in which a flow of water occurs, either continuously or intermittently, and if the latter with some degree of regularity. Watercourses may be either natural of artificial.

M.T.  "Water Quality Control/Pollution Reduction Facility." Refers to any structure or drainageway or drainage device that is designed, constructed, and maintained to collect and filter, retain, or detain surface water runoff during and after a storm event for the purpose of maintaining or improving surface and/or groundwater quality. These facilities may include, but are not limited to, constructed wetlands, water quality swales, and ponds which are maintained as stormwater quality control facilities.

N.U.  "Water Quantity Control Facility." Refers to any structure or drainage device that is designed, constructed, and maintained to collect, retain, infiltrate, or detain surface water runoff during and after a storm event for the purpose of controlling post-development quantity leaving the development site. These facilities may include, but are not limited to, constructed wetlands, infiltration basins, and wet ponds which are maintained as stormwater quantity or quality control facilities.

O.V.  "Wetland." An area that is inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances does support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands include swamps, marshes, bogs, and similar areas except those constructed as water quality or quantity control facilities. Specific wetland designations shall be made by the Corps of Engineers and the Division of State Lands.

The remainder of this section is unchanged

c.  Section 17.38.040 is amended as follows:

C.1.a. The information required in an operation and maintenance plan shall satisfy the requirements of the City of Portland's "Stormwater Management Manual (SWMM)". Applicants are encouraged to use the O & M Plan template provided in the SWMM. The Plan which shall include but and not be limited to:

(1)  Design plans of the specific facility and related parts, including design assumptions.

(2)  A schedule for routine inspection, including post storm related inspections. A detailed description of how the facility is intended to operate.

(3)  A description of the various facility components, the observable trigger for maintenance, and the method of maintenance, including appropriate method of disposal of materials. A description of the maintenance practices necessary for the continued functioning of the facility.

(4)  A maintenance schedule for the entire facility and its various parts.

(5)  (4)  The intended method of providing financing to cover future operations and maintenance.

(6)  (5)  The party or parties responsible for maintenance of the facility including means of effecting contact, including contact means for emergency situations. The party may be an individual or an organization.

(7) 1.b. A maintenance log is required. The log shall provide a record of all site maintenance related activities. The log shall A maintenance log includinge the time and dates of facility inspections and specific maintenance activities. The log shall be available to City inspection staff upon request.

C.3. A copy of the operation and maintenance plan shall be filed with the bBureau of Environmental Services. Staff may require a site map operations and maintenance plan to be recorded and filed with the appropriate county Department of Assessment and Taxation.

The remainder of this section is unchanged

d.  Section 17.38.021 is amended as follows:

A.  Authority. The Director may require drainage reserves or tracts over seeps, springs and drainageways as necessary to preserve the functioning of these areas and to limit flooding impacts from natural and man made channels, ditches, seeps, spring, intermittent flow channels and other open linear depressions. Standards and criteria for imposing drainage reserves or tract requirements shall be adopted by administrative rule. Placement and/or sizing of drainage reserves does not relieve property owners of their responsibility to manage stormwater in a manner that complies with the duties of property owners under applicable law. Drainage reserve or tract requirements may be imposed during land use reviews, building permit review or other development process that require Bureau of Environmental Services review

B.  Required Management of the Drainage Reserve. Storm drainage reserves or tracts shall remain in natural topographic condition. No private structures, culverts, excavations, or fills shall be constructed within drainage reserves or tracts unless authorized by the BES Chief Engineer. All changes must also comply with other zoning regulations as described in Title 33.

The remainder of this section is unchanged.

e.  Section 24.10.030 is amended as follows:

Scope. (Amended by Ordinance No. 163237, 163908; and 165678, effective July 15, 1992.) The provisions of this Title shall apply to the construction, alteration, moving, demolition, repair, and use of any building, structure or land, and to any land clearing or grading within the City. Exceptions are work in the public right-of-way as approved by the City Engineer; publicly constructed sanitary and storm sewer systems and facilities approved by the BES Chief Engineer; and public utility towers and poles, mechanical equipment not specifically regulated in this Code. ; and City owned or maintained hydraulic flood control structures and water quality control facilities as defined by Title 17 of the Code of the City of Portland.

f.  Section 24.10.070 is amended as follows:

A.  Permits required. No person, firm, or corporation shall erect, construct, enlarge, alter, repair, move, improve, remove, convert, change occupancy group of, or demolish any building or structure, or to do any clearing or grading, or cause any of the same to be done without first obtaining a building permit, or where appropriate a minor structural label as outlined in Section 24.10.095. Building permits and fees for work on private property is waived whenever the work appears on plans and specifications, approved by the City Engineer or BES Chief Engineer. This work shall be limited to the construction of streets, public sewers, public stormwater management facilities, driveways, retaining walls, fences, walkways, parking pads, steps, and tree, shrub, and brush removal.

The remainder of this section is unchanged.

Passed by the Council,  JUL 31 2002      Gary Blackmer

Mayor Vera Katz            Auditor of the City of Portland

             By /S/ Terry Reisz

Patrice Mango

July 8, 2002              Deputy

14531043 - ord

BACKING SHEET INFORMATION

AGENDA NO. 904, 960-2002

ACTION TAKEN:

JUL 24 2002 PASSED TO SECOND READING JUL 31 2002 9:30 A.M.

ORDINANCE/RESOLUTION/COUNCIL DOCUMENT NO. 176783