Warsaw City Zoning Code
§ 405.070
Stormwater Management and Natural Area Protection Standards.
[Ord. No. 211 § 2, 12-21-2015; Ord. No. 527, 12-26-2023]
A.
Purpose. The City contains many natural amenities, including stream corridors, river corridors, natural drainage paths, significant viewsheds and hillsides, as well as tree cover, and open space, all of which contribute to stormwater management and flood risk reduction as well as the City's character, quality of life and property values. The regulations of this Section are intended to implement the Warsaw Comprehensive Plan and stormwater management design criteria to ensure that the natural character of the City is reflected in patterns of development and redevelopment, and significant natural features are protected and incorporated into open space areas. This Section regulates stormwater management for development and redevelopment, as well as uses and activities within identified stormwater drainage setbacks, to preserve, conserve and manage disturbance to the City’s stream corridors so that the following objectives may be achieved:
1.
Encourage sustainable and healthy development practices that benefit the community as a whole;
2.
Protect the public by preventing or regulating development in hazardous areas, such as locations within natural drainage paths or on steep slopes;
3.
Mitigate impacts to the public from stream erosion and degradation;
4.
Encourage only minimal grading that relates to the natural contour of the land;
5.
Discourage mass grading activities, excessive tree and vegetation removal, and excessive terracing;
6.
Improve surface and ground water quality by reducing the amount of nutrients, sediment, organic matter, pesticides, and other harmful substances that reach watercourses, wetlands, subsurface and surface water bodies;
7.
Recognize that natural features contribute to the welfare and quality of life of the City’s residents;
8.
Provide natural, scenic, and recreation areas within and adjacent to stormwater drainage setbacks for community’s benefit, thereby creating added value to lands adjacent to natural drainage paths and streams.
B.
Definitions.
1.
BEST MANAGEMENT PRACTICE (STORMWATER BMP): post-construction, permanent stormwater BMPs designed to manage stormwater runoff. Stormwater BMPs may also be referred to as green stormwater infrastructure practices.
2.
DRAINAGE EASEMENT: Authorization by the property owner to the public, a corporation or persons of the use of an area of land for stormwater management purposes.
3.
GREEN STORMWATER INFRASTRUCTURE (GSI): Stormwater management solutions designed to capture, filter, absorb, and/or re-use stormwater by mimicking natural hydrologic processes. GSI may also be referred to as stormwater BMPs.
4.
NATURAL DRAINAGE PATH: The overland route in which water concentrates based on the natural topography of the land. Natural drainage paths function as the surface drainage component of a stormwater drainage system and represent the path stormwater will take when the design capacity is exceeded in the enclosed system. Natural drainage paths typically begin with approximately two (2) acres of drainage area.
5.
STREAM CORRIDOR: Perennial or intermittent waters included within a channel of land, and its adjacent riparian zones, which serve as a transitional zone between the aquatic and terrestrial upland ecosystems.
6.
STORM DRAINAGE SYSTEM: All of the natural and man-made facilities and appurtenances such as natural drainage paths, streams, pipes, culverts, bridges, open channels, swales, street gutters, inlets, retention/detention facilities, and stormwater BMPs/GSI which serve to convey and control surface drainage.
7.
STORMWATER DRAINAGE SETBACKS: Preservation of vegetated areas adjacent to a natural drainage path or stream defined by the drainage easement with limitations on allowable development and uses. Stormwater drainage setbacks consist of preservation, protection, and limited-use setback zones.
8.
TOP OF BANK: The vertical point along a stream bank where an abrupt change in slope is evident, typically representative of the bank-full or channel-forming flow caused by approximately the two-year design storm as defined by the City’s stormwater management design criteria.
C.
Stormwater Management Requirements. All improvements shall be in compliance with the City’s stormwater management design criteria, per Section 500.050, City of Warsaw Standards and Procedures for Design and Construction. Applicability standards are set forth in 405.030(O), Drainage Permit. The applicant shall follow the procedures established in Section 405.030 to demonstrate compliance with the design criteria.
D.
Natural Drainage Path Preservation. Natural drainage paths and stream corridors shall be preserved and protected by limiting development activity in and adjacent to these areas to reduce risk of property damage from flooding and stream bank erosion, and to protect the safety of the public.
1.
Natural drainage path requirements. Site design shall not change natural drainage paths. Natural drainage path preservation shall be as follows:
a.
All final grading and drainage shall comply with applicable City and State requirements.
b.
To the maximum extent feasible, development shall preserve the natural drainage paths unique to each site as a result of topography and vegetation. Natural drainage paths may be modified on site only if outside of the stormwater drainage setback. If natural drainage paths are modified, appropriate stabilization techniques shall be employed.
c.
Streets, roads, private access roads and other vehicular routes shall, to the maximum extent feasible, not be constructed within a natural drainage path.
d.
Grading shall be designed such that drainage flows away from all structures and heavily used areas.
e.
Development shall be designed to mitigate all negative or adverse drainage impacts, such as flooding and erosion, on adjacent and surrounding properties.
2.
Stormwater drainage setbacks. Stormwater drainage setbacks shall apply to all land or development that includes natural drainage paths as defined herein and identified in the stormwater management design criteria. The requirements for stormwater drainage setbacks are as follows:
a.
The stormwater drainage setback shall start at the top of bank of the natural drainage path/stream, to be determined by topographic survey, and move outward on either side of the channel. If a top of bank cannot be determined, one (1) of the following methods may be applied to define the top of bank for the stormwater drainage setback:
(1)
Apply the assumed channel width to the centerline of the natural drainage path.
(2)
Delineate the bank-full or channel-forming flow caused by approximately the two-year rainfall event as defined by the City’s stormwater management design criteria.
b.
Stormwater drainage setbacks shall be identified on the site plan and dedicated on the preliminary and final plats as a Drainage Easement.
c.
Stormwater drainage setback widths have been determined based on tributary drainage area, as shown in Table 405.070-1 and Figure 405.070-1, with the following defined setback widths:
(1)
Channel Width: centered on the natural drainage path is preserved for frequent stormwater flows with no other allowable uses.
(2)
Preservation Setback Width: begins at the top of bank of the natural drainage path/stream and is preserved for vegetation or other forms of bank stabilization with no other allowable uses.
(3)
Limited-Use Setback Width: extends a predetermined distance from the preservation setback or to the extents of the 100-year effective FEMA floodplain, whichever is greater. Allowable uses within the limited-use setback include community amenities such as trails and greenways, as well as utility rights-of-way.
Table 405.070-1 | ||||
|---|---|---|---|---|
Stormwater Drainage Setbacks | ||||
Drainage Area (acre) | Assumed Channel Width (feet)* | Preservation Setback Width (feet) | Limited-Use Setback Width (feet) | Total Setback Width (feet) |
2 to < 10 | 5 | 5 | – | 15 |
10 to < 40 | 10 | 10 | 10 | 50 |
40 to < 160 | 30 | 30 | 10 | 110 |
160 to < 640 | 60 | 60 | 20 | 220 |
640+ | 80 | 80 | 20 | 280 |
* Actual channel width may differ from Assumed Channel Width values presented in table based on results of topographic survey. | ||||
Figure 405.070-1: Stormwater Drainage Setbacks |
|---|
 |
d.
No construction or disturbance of any type, including clearing, grubbing, stripping, fill, excavation, linear grading, paving, or building is allowed in the setback zones except as falls within the allowable setback uses or by permission of the City Engineer. Dense stands of native vegetation shall be maintained, particularly in the preservation setback.
e.
Unless otherwise accepted by the Director, any maintenance of stormwater drainage setbacks shall be the responsibility of the property owner.
f.
For work on existing facilities already located closer to the stream than allowed above, the improvements shall not increase the encroachment any closer to the stream. Bank stability concerns shall be addressed for improvements to existing land within the setback zones. Formal designation of a stormwater drainage setback is not required.
g.
The application of stormwater drainage setbacks shall not operate to deprive any landowner of substantially all of the market value of their property or otherwise constitute an unconstitutional taking without compensation. If application of the stormwater drainage setbacks to a specific project would create a taking, then the Board of Aldermen may allow a variance, but only to the extent necessary to avoid a taking.
E.
Drainage Easements. All storm drainage systems shall be placed in a drainage easement, per the City of Warsaw’s stormwater management design criteria. If a subdivision is traversed by a natural drainage path or stream, a stormwater drainage setback shall be applied per Table 405.070-1. The entirety of the stormwater drainage setback shall be placed in a drainage easement to provide adequate stormwater drainage and for access for maintenance thereof.
F.
Maintenance Agreements. Any person engaged in work of development or redevelopment that requires a drainage easement shall enter into a stormwater management operations and maintenance agreement assuring the continued operation and maintenance of such stormwater management components by the property owner and allowing access and inspection by the City. The agreement shall be recorded in the office of the Register of Deeds and be binding upon all owners of the property.
G.
Grading Plan; Revegetation Of Disturbed Sites. A grading plan, submitted pursuant to Section 405.030(N), Grading Permit, and demonstrating compliance with the above standards is required. The grading plan shall include a section outlining the type and extent of revegetation proposed to accomplish the following requirements:
1.
Following construction, the site shall be reclaimed and revegetated following the standards of Section 405.120, Landscaping and Screening.
2.
In areas of subdivisions and large lot development sites, phased grading and revegetation is preferred.
3.
In areas of subdivisions and development sites where landscaping is not required or not anticipated by the Director, the developer shall reclaim all disturbed property and replant the entire area with native vegetation as described in Section 405.120, Landscaping and Screening.
4.
Temporary or permanent irrigation shall be provided to the revegetated areas if the City Engineer determines that it is necessary.
H.
Erosion Prevention And Sediment Control. Erosion control methods shall be used during construction to protect water quality, control drainage, and reduce soil erosion in accordance with Section 500.050, City of Warsaw Standards and Procedures for Design and Construction. All new development shall be subject to the following erosion prevention and sediment control standards:
1.
Compliance with applicable City and State requirements.
2.
Water shall be managed within the site to a pre-project conditions. Site disturbance shall cause no adverse impacts downstream. Erosion and sediment control shall contain erosion and sediment on the site, and protect stormwater management infrastructure within the site during construction.
3.
Erosion control measures as necessary to control erosion and sedimentation during site development and construction shall be implemented.
I.
Steep Slope And Ridgeline Development.
1.
Purpose. The purpose of this Subsection is to:
a.
Prevent soil erosion and landslides;
b.
Protect the public by preventing or regulating development in hazardous areas, such as locations with steep slopes;
c.
Provide safe circulation of vehicular and pedestrian traffic to and within hillside areas and provide access for emergency vehicles necessary to serve the hillside areas;
d.
Preserve the most visually significant slope banks and ridgelines in their natural state;
e.
Preserve visually significant rock outcroppings, native plant materials, natural hydrology and other areas of visual significance;
f.
Encourage variety in building types, grading techniques, lot sizes, site design, density, arrangement and spacing of buildings in developments;
g.
Encourage innovative architectural, landscaping, circulation and site design; and
h.
Require revegetation and reclamation of slopes disturbed during development.
2.
Applicability. This Subsection shall apply to any development or subdivision proposal or lot created after December 21, 2015, for properties with an average slope of fifteen percent (15%) or greater, or where adverse conditions associated with slope stability, erosion or sedimentation are present as determined by the City Engineer. Determinations of adverse conditions shall be identified by the City Engineer within ten (10) days of applicable application filing.
3.
Development on slopes greater than twenty percent (20%). Site areas with slopes greater than twenty percent (20%) shall remain undisturbed except as follows:
a.
This requirement shall not apply to small, isolated steep slope areas within a site that do not exceed two thousand five hundred (2,500) square feet.
b.
Slope areas of twenty percent (20%) or greater shall count toward minimum lot size, as defined in Section 405.040, Zoning Districts.
c.
Development is permitted outside of the slope area of twenty percent (20%) if the Director determines that there is sufficient buildable area on the lot for the proposed structure.
4.
Development on slopes between fifteen percent (15%) and twenty percent (20%). The following standards apply to site design for all proposed development on sites where the average slope of the site measures between fifteen percent (15%) and twenty percent (20%).
a.
Roads and building sites shall be oriented to minimize grading.
b.
Buildings shall be oriented to consider views from the site as well as the aesthetic impact of views of the site from surrounding properties.
c.
Hilltops, if graded, should be rounded to blend with natural slopes rather than leveled.
d.
Slopes providing a transition from graded areas into natural areas should be varied in percent grade both up-slope and across the slope, in the undulating pattern of surrounding natural slopes so that the top or the toe (or both) of the cut or fill slope will vary from a straight line in plan view.
e.
Parking areas should be constructed on multiple levels and follow natural contours as necessary to minimize cut and fill.
f.
Roads should follow natural topography to the extent feasible, to minimize cut and fill. Necessary grading should be constant half-cut and half-fill along the length of the road (versus all cut or all fill at points) unless other arrangements would result in less severe alteration of natural terrain.
g.
Typical design should utilize full split pads (separate level for a down-slope lower story), a split foundation (adapting a single story to a slope), setting the building into a cut in the hillside, or a combination of techniques. Repetitive padding or terracing of a series of lots (stair-stepping up a slope) is discouraged. Creation of a single large pad or terrace (especially creating a single pad or terrace of an entire lot) should be an exception to typical design to deal with circumstances that cannot be managed with other techniques.
5.
Utilities on slopes. Where buried utilities are placed on side slopes and where the utility corridor runs transverse to the side slope, the side slope portion of the corridor shall be no more than ten percent (10%).
6.
Cutting, grading and filling.
a.
Cutting and grading to create benches or pads for buildings or structures shall be avoided to the maximum extent feasible.
b.
Except for driveways, cut and fill slopes shall be entirely contained within a lot (i.e., natural grade at the lot lines shall be maintained).
c.
Sharp angles shall be rounded off in a natural manner at the top and ends of cut and fill slopes [within approximately five (5) feet of the sharp angle] unless steep angles are a natural character of the site. Where this would damage tree root systems, the amount of rounding off may be reduced and shrubs used instead to hide the transition.
7.
Raising or lowering of natural grade. The original, natural grade of a lot shall not be raised or lowered more than four (4) feet at any point for construction of any structure or improvement, except:
a.
The site's original grade may be raised or lowered a maximum of six (6) feet if retaining walls are used to reduce the steepness of man-made slopes.
b.
As necessary to construct a driveway from the street to a garage or parking area, grade changes or retaining walls up to six (6) feet may be allowed.
c.
For the purposes of this Subsection, basements and buildings set into a slope are not considered to lower the natural grade within their footprint.
8.
Vehicular routes. The following regulations apply to vehicular routes on slopes of fifteen percent (15%) or greater.
a.
No street, road, private access road, driveway or other vehicular route shall cross slopes greater than fifty percent (50%).
b.
Streets, roads, private access roads, driveways and other vehicular routes shall not be allowed to cross slopes between thirty percent (30%) and fifty percent (50%), except that a short run of no more than one hundred (100) feet or ten percent (10%) of the road/street's entire length, whichever is less, may be allowed by the Director upon finding that:
(1)
Such street or road will not have significant adverse safety or environmental impacts, or appropriate engineering or other measures will be taken by the developer to substantially mitigate any such adverse impact; and
(2)
No alternate location for access is feasible or available.
c.
Streets, roads, private access roads and other vehicular routes shall, to the maximum extent feasible, follow natural contour lines and not be within a natural drainage path.
d.
Grading for streets, roads, private access roads and other vehicular routes shall be limited to the paved portion of the right-of-way, plus up to an additional ten (10) feet on either side of the paved portion as needed, except that when developing access on slopes in excess of twenty-five percent (25%) only the paved right-of-way shall be graded, plus the minimum area required for any necessary curb, gutter or sidewalk improvements. The remainder of the access right-of-way shall be left undisturbed to the maximum extent feasible.
9.
Trails. Public trails are permitted on all slopes provided proper safety buffers are in place. Private trails may be allowed if the Director determines that there will be no significant adverse impacts.