§ 19A-1-2-123. Responsibility of developer/owner for storm drainage improvements.

It shall be the responsibility of the developer/owner to control the stormwater runoff leaving his/her property and not to cause a change in the historic runoff characteristics of the upstream or downstream area. The developer/owner shall also not cause the existing storm drainage system to exceed the capacity as defined in the Stormwater Drainage Policy. To achieve this the developer/owner shall provide stormwater storage and stormwater drainage system improvements for the increased stormwater runoff resulting from his development in accordance with the following requirements and the Stormwater Drainage Policy.

A.

Where a developer/owner proposes development or use of only a portion of the property, provision for storm runoff improvements shall be required at least for that portion of the property proposed for immediate development or use.

B.

When a proposed development receives runoff from upstream and/or from adjacent property which can be developed in the future, the developer/owner of a proposed development shall provide a sufficient stormwater drainage system for the conveyance of flows for full development from those sources and the "added" flow from his/her property.

C.

All roofs, paved areas, yards, courts, and courtyards, other than one-family or two-family residential structures, shall drain into an existing or improved storm sewer system or to an approved place of disposal, not generally including streets.

D.

The release of stormwater in excess of historic values onto streets may be considered acceptable if: the peak flow from the site does not increase and:

1.

When the release of additional stormwater is "added" to the existing street flow, the combined flow does not exceed the design criteria for street flow as set forth in the Stormwater Drainage Policy; and

2.

The stormwater conveyance system of streets, inlets, pipes, flumes and swales from this entry point to downstream where this stormwater discharges into a primary channel or regional detention site is adequately sized to handle this additional flow without exceeding their capacity per design criteria in the Stormwater Drainage Policy.

E.

In the case of one- and two-family residential structures, stormwater may be discharged onto flat areas such as driveways or lawns if drainage is provided so that the stormwater will flow away from the building and not adversely affect adjacent properties, and if the requirements of the Stormwater Drainage Policy are met. A lot and block grading plan shall be used to ensure lots are graded in accordance with the overall grading plan for the block.

F.

The developer/owner shall be responsible for the construction, operation and maintenance of all privately owned stormwater detention systems. No conveyance of the responsibility of the detention system is implied by the issuance of building permits. Stormwater detention systems shall generally be considered a priority during development and constructed prior to any change in the stormwater runoff of the development. The construction of stormwater storage facilities required as a part of proposed subdivision developments may be delayed for a twelve month period following the effective date of this ordinance provided the developer furnish a performance bond or cash escrow account in the amount of 125% of the estimated construction cost of said stormwater storage facilities, however design of said facilities shall be submitted and approved with the construction plat for the development.

G.

The developer/owner shall be responsible for the design, installation, and continual maintenance of all erosion and sediment control Best Management Practices (BMPs). The Developer/Owner shall obtain the necessary permits from the City of Lawton and the Oklahoma Department of Environmental Quality prior to any construction activities. Installation of erosion and sediment control BMPs is considered the number one priority before construction activity takes place. Appropriate and acceptable BMPs are outlined in the Stormwater Drainage Policy.

H.

Development of a parcel or tract of land less than one acre in size and not part of a larger common plan of development will be exempt from the requirement to provide detention.

(Ord. 2006-39, Amended, 06/27/2006; 2005-92, Added, 02/01/2006)