[HISTORY: Adopted by the Common Council of the City of Lodi as Ch. 34 of the City Code. Amendments noted where applicable.]
The definitions in Chapter 300, Subdivision of Land, § 300-2 shall apply to this chapter. The term "development," when used in this chapter, shall mean the performance of any of the activities described in § 162-2 or, where the context so requires, a project in its finished state after development has taken place. The term "developer" shall mean any person who undertakes the act of development.
This chapter shall apply to the following activities:
The creation of any land division, subdivision or minor subdivision.
Any building, construction, land disturbing or land filling project on land:
For which a drainage plan has not been previously approved under the City of Lodi ordinances;
Where such project was not considered when the drainage plan for the land was approved; or
Where such project deviates from the activities that were considered when the drainage plan for the land was approved.
A complete and adequate drainage system design and installation shall be required for the activity and may include a storm sewer system or a system of open ditches, culverts, pipes and catch basins, or both systems. The system shall be designed to minimize the impact of stormwater discharge to downstream properties and shall be designed in conformity with all applicable standards of the City. No building construction, land disturbing or land filling operations on the land involved shall commence until the drainage system design has been approved in writing by the City Engineer.
Drainage and storage facilities shall be designed using the Soil Conservation Service Urban Hydrology Method (SCS TR 55 or SCS TR 20) of calculating runoff discharge rate and total volume.
The allowable release rate from the proposed development shall not exceed the release rate of the site in its predeveloped condition up to and including the fifty-year design storm. Location and design of runoff control measures shall take into consideration soil types, slopes, and existing groundwater conditions in the area in order to avoid property damage due to increased elevations of groundwater or due to soil saturation. In no case shall the predevelopment condition have runoff curve numbers greater than those listed below:
The increased stormwater runoff resulting from the proposed activity may be accommodated by the provision of appropriate detention facilities, including wet or dry bottom reservoirs, flat roofs, parking lots or underground storage. The following shall govern the design of on-site detention facilities:
Volume. The volume available in the detention facilities shall be sufficient to store the excess stormwater runoff calculated for the developed condition with a release rate which does not exceed the predeveloped condition. The predevelopment release rate shall not be exceeded regardless of the depth of water in the detention basin.
Release velocity. Detention facilities shall release water at a nonerosive velocity. Receiving channels shall be protected with energy-dissipating devices such as stone riprap. This may require construction of an energy-dissipation structure or device at the outfall into the channel. Smooth pavement shall not be allowed. If a stable stand of grass is not established in the receiving channel, the channel shall be lined with erosion matting up to the elevation of the five-year design storm discharge rate under development conditions.
Freeboard. Detention facilities shall have adequate capacity to contain the storage volume of tributary stormwater runoff with at least six inches of freeboard above the water surface of flow in an emergency spillway in a fifty-year, twenty-four-hour storm.
The City may, at its option, require that wet or dry bottom reservoirs or underground water storage facilities be dedicated to the public and thereby become owned by the City, in which case the City shall be responsible for maintenance thereof. If the City does not so elect, the owner of the property on which such facilities are located shall be responsible to maintain such facilities, although the City shall, in all cases, have the right to provide such maintenance in the event the property owner fails to do so. Appropriate easements for such purpose shall be provided by the developer to the City. If the City provides maintenance services otherwise required of the property owner, the costs of providing such services may be imposed as a special charge against the property on which the facility is located pursuant to § 66.0627, Wis. Stats.
Stormwater runoff from impervious surfaces such as roofs, parking and loading areas and driveways shall be directed to public stormwater channels and where possible across a stable pervious surface such as a lawn area or grass-lined channel. Where the topography prevents discharge of stormwater to a public right-of-way or storm sewer, or dedicated drainage easement, the developer must prevent release of stormwater from the property at a rate greater than the predevelopment condition. This requirement may be waived if the developer obtains an easement from downstream landowners lying between the subject property and the outlet to a public channel or right-of-way.
Easements shall be provided along each side of the center line of any watercourse or drainage channel, whether or not shown in the Comprehensive Plan or Official Map, to a sufficient width to provide proper maintenance and protection and to provide for stormwater runoff. Such easements shall provide for installation and maintenance of storm sewers, drainage swales or other associated appurtenances.
The developer shall submit to the City a preliminary drainage plan or engineering report on the proposed improvements pertaining to drainage and stormwater control. This report shall contain information on the existing conditions at the site, including existing and proposed drainage directions and elevations and slopes of all nearby drainage facilities. Runoff calculations shall be provided for the site in both predeveloped and developed conditions, and off-site drainage to the site shall be addressed. Where practical, this submittal may be combined with the erosion control plan submittal required under Chapter 147, Construction Site Erosion Control.
Those development projects determined by the Building Inspector as not involving a significant impact on neighboring properties or regional stormwater systems may be processed informally. The applicant shall submit a plot plan showing the proposed development with existing and proposed direction of drainage delineated. The Building Inspector shall determine whether or not the application can proceed informally and, if so, provide written notification of the requirements for compliance with City standards on small stormwater quality measures, such as berms, swales or rain garden infiltration areas, direction of flows to the appropriate channels, and, if appropriate, compliance with Chapter 147, Construction Site Erosion Control. The applicant shall sign a statement acknowledging the applicant's receipt of and agreement to comply with these terms. The Building Inspector can decline to approve a small impact project exception under this section upon determining that the site impacts too heavily upon the stormwater system to be approved without full review. The result of such a decision by the Building Inspector shall be to require full application and processing. The Building Inspector may consult with the Director of Public Works before approving a small impact project exception under this section. Such officials may consult with the City Engineer with respect to any issues under this section if either of such officials deems such consultation appropriate.