[Ord. No. 2772 §1, 5-20-2002]
No development shall increase the quantity or rate of storm
water emanating from said land areas) except in accordance with an
approved storm water management plan as provided in this Storm Water
Management Ordinance. A professional engineer licensed in the State
of Missouri shall prepare the storm water management plan. The City
Engineer shall issue no permits prior to the approval of the storm
water management plan.
[Ord. No. 2772 §1, 5-20-2002]
A.
Residential Subdivisions.
1.
Individual lots in a residential subdivision development shall not
be considered to be separate land disturbing activities and shall
not require individual permits; whereas, the residential subdivision
development, as a whole, shall be considered to be a single land disturbing
activity. Hydrologic parameters that reflect the ultimate subdivision
development shall be used in all engineering calculations.
2.
If individual lots or sections in a residential subdivision are being
developed by different property owners, all land disturbing activities
related to the residential subdivision shall be covered by the approved
storm water management plan for the residential subdivision. Individual
lot owners or developers shall be responsible for all activities on
that lot and that they will be carried out in accordance with the
approved storm water management plan for the residential subdivision.
3.
Residential subdivisions which were approved prior to the effective
date of these regulations are exempt from these requirements. Development
of new phases of existing subdivisions, which were not previously
approved, shall comply with the provisions of these regulations.
B.
Residential
land disturbing activities involving less than 1 (one) acre of actual
land disturbance which are not part of a larger common plan of development
or sale, the person responsible for the land disturbing activity shall
submit a simplified storm water management control plan meeting the
requirements listed below. This plan does require approval by the
City Engineer and does not require preparation or certification by
the engineer specified in this Storm Water Management Ordinance.
1.
A narrative description of the storm water management facilities
to be used.
2.
A general description of topographic and soil conditions of the development
site.
3.
A general description of adjacent property and a description of existing
structures, buildings and other fixed improvements located on surrounding
properties.
4.
A sketch plan to accompany the narrative which shall contain:
a.
A site location drawing of the proposed project, indicating the location
of the proposed project in relation to roadways, jurisdictional boundaries
and receiving storm drainage systems including conduits, channels,
lakes, streams and rivers;
b.
The boundary lines of the site on which the work is to be performed;
c.
All areas within the site which will be included in the land disturbing
activities shall be identified and the total disturbed area calculated;
d.
A topographic map of the site or property survey;
e.
Anticipated starting and completion dates of the various stages of
land disturbing activities and the expected date the final stabilization
will be completed;
f.
The location of temporary and permanent vegetative and storm water
management control measures.
5.
Storm water management plans shall contain certification by the persons
responsible for the land disturbing activity that the land disturbing
activity will be accomplished pursuant to the plan.
6.
Storm water management plans shall contain certification by the person
responsible for the land disturbing activity of the right of the City
Engineer to conduct on-site inspections.
[Ord. No. 2772 §1, 5-20-2002]
A.
A preliminary
storm water plan and design report shall accompany all preliminary
applications for land development. This preliminary plan shall contain,
but not be limited to, the following information and data:
1.
A site plan of suitable scale and contour interval showing existing
topographic information of the land to be developed and adjoining
land whose topography may affect the proposed layout or drainage patterns
for the development. A general plan of proposed grading contours of
the site development shall also be shown as shall all existing culverts,
pipe systems, streams, waterways, channels, and the extent of the
established floodplains as defined on the current FIRM;
2.
The location and calculated flow rates of all adjacent storm water
management facilities;
3.
A general discussion of the type and characteristics of soils contained
in the development area;
4.
Hydrologic and hydraulic analysis with a description of the concept
considered in the development to manage anticipated storm water runoff
including the methods utilized to detain or control storm water runoff
generated by the proposed development;
5.
A preliminary plan of proposed storm water management facilities
(detention, conveyance systems, floodplains, erosion control, etc.)
including grading, alignments and preliminary engineering calculations;
6.
A discussion of the possible effects that the proposed development
could have on areas adjoining the development.
B.
The
expected timing of flood peaks through the downstream drainage system
shall be assessed when planning the use of detention basins.
C.
All
storm water management facilities and all major portions of the conveyance
system through the proposed development (i.e., channels, culverts)
shall be analyzed, using the 10- and 100-year storms, for design conditions
and operating conditions which can reasonably be expected during the
life of the facility. The results of the analysis shall be included
in the hydrologic-hydraulic analysis.
D.
The
storm water analysis shall continue downstream of the development
to a point where the development contributes ten percent (10%), or
less, of the overall watershed. If the storm water management plan
indicates that there may be a drainage or flooding problem within
this area downstream of the development, the City Engineer may require:
E.
All
storm water management plans submitted for approval shall contain
certification by the person responsible for the land disturbing activity
that the land disturbing activity will be accomplished pursuant to
the approved plan and that responsible personnel will be assigned
to the project.
F.
All
storm water management plans shall contain certification by the person
responsible for the land disturbing activity of the right of the City
Engineer to conduct on-site inspections.
G.
The
storm water management plan shall not be considered approved without
the inclusion of an approval stamp and date and the signature of the
City Engineer. The stamp of approval on the plans is solely an acknowledgment
of satisfactory compliance with the requirements of these regulations.
The approval stamp does not constitute a representation or warranty
to the applicant or any other person concerning the safety, appropriateness
or effectiveness of any provision, or omission from the storm water
management plan.
H.
Approved
storm water management plans remain valid for five (5) years from
the date of an approval. Extensions or renewals of the plan approvals
will be granted by the City Engineer upon written request by the person
responsible for the land disturbing activity.
I.
Following
the receipt of the preliminary storm water management plan, a review
meeting may be conducted. The purpose of this review shall be to jointly
agree on the methods proposed to be utilized and the possible effects
of the proposed development on existing and future adjacent developments.
If any known downstream problems exist, the City Engineer may require
additional improvements.
J.
All
preliminary plats of the development shall be consistent with the
preliminary storm water plan.
K.
Upon
approval of the preliminary plan, the applicant shall submit a final
storm water management plan (as part of the construction plans) to
the City Engineer for review and approval.
[Ord. No. 2772 §1, 5-20-2002]
A.
Following
the review and general approval of the preliminary storm water management
plan by the City Engineer, a final storm water management plan and
design report shall be prepared for each phase of the proposed project
as each phase is developed. The submittal of the final plan shall
coincide with the application for final approval of the development
and shall constitute a refinement of the concepts approved in the
preliminary plan. It is important to note that if a project is to
be phased, the total area of the project is to be considered in all
calculations, and that facilities should be designed for each phase
which would be compatible with those of the total development plan.
The final storm water management plan shall be prepared and sealed
by a registered professional engineer.
B.
The
final storm water management plan for any development shall include,
but not be limited to, the following information unless specifically
allowed to be excluded by the City Engineer.
1.
A topographic map of the project site and adjacent areas, of suitable
scale and two (2) feet minimum contour intervals, which shall define
the location of all existing and proposed storm water management facilities
and regulatory floodplains and floodways. Existing storm water facilities
within two hundred (200) feet of the property shall be mapped or as
approved by the City Engineer;
2.
The location and flowline elevations of all existing sanitary facilities
and the location of any existing sewage treatment facilities which
fall within the project limits;
3.
Detailed determination of runoff anticipated for the entire project
site and upstream areas following development. The proposed runoff
calculations shall indicate the design size, land uses, hydrologic
factors, rates, and volumes for the project subareas and their effects
within the overall watershed, including analysis of methods to manage
runoff;
4.
A layout of the proposed storm water management facilities including
the location and size of all drainage structures, conduits, channels,
detention basins, and analyses regarding the effect that said improvements
will have upon the upstream and downstream facilities;
5.
The slope, type, length, size, flow, headwater and velocity calculations
for all existing and proposed storm water management facilities;
6.
Existing and future conditions hydrographs of inflow and outflow
from the watershed including the site along with proposed development
conditions hydrographs for any detention basin(s);
7.
Plot or tabulation of stage-storage volumes with corresponding stage-discharge
rates for any proposed detention basin(s);
8.
Profiles and cross sections of all existing and proposed storm water
management facilities showing existing conditions and the proposed
changes thereto including, but not limited to, conduits, channels,
streets, buildings, sewers, utilities, inlets, manholes, junction
boxes, ground grade lines, and the design hydraulic grade lines;
9.
Permitting applications with supporting data such as NPDES Erosion
Control Plans, FEMA Map Revisions or Amendments, COE Section 404 Permits,
and MDNR 401 Water Quality Certification and the Dam and Reservoir
Safety Program.
C.
The
storm water management plan shall contain certification by the applicant
that all land clearing, construction, development and drainage will
be done according to the storm water management plan or previously
approved revisions.
D.
The
final storm water management plan shall be reviewed by the City Engineer.
If it is determined that the proposed development will provide control
of storm water runoff in accordance with the purpose, design criteria,
and performance standards of the Storm Water Management Design Manual
and these ordinances and will not be detrimental to the public health,
safety and general welfare, the City Engineer shall approve the plan
or conditionally approve the plan setting forth the conditions thereof.
E.
Should
any storm water management plan involve any storm water management
facility or land to be dedicated to public use, the same information
shall also be submitted for review and approval to the department
having jurisdiction over the land or other appropriate departments
or agencies for review and approval. This storm water management plan
shall serve as the basis for all subsequent construction.
F.
The
City Engineer shall review the storm water management plan within
thirty (30) working days from and after the receipt of all required
information.
[Ord. No. 2772 §1, 5-20-2002; Ord.
No. 3637, 3-20-2023]
Storm water management plans shall include, as a minimum, the
following.
A.
A vicinity map indicating a north arrow, scale, boundary lines of
the site, existing and proposed easements, utilities, regulatory floodplains,
and other information necessary to locate the development site.
B.
The existing and proposed topography of the development site except
for individual lot grading plans in single-family subdivisions. Include
available geotechnical data such as soil boring's location and soil/rock
depth and classifications.
C.
Physical alterations of the site, including existing development
and proposed development.
D.
Location, dimensions, elevations and capacities of all existing and
proposed storm water management facilities, including plan, profiles
and construction details.
E.
All areas within the site which will be included in the land disturbing
activities shall be identified and the total disturbed area calculated.
F.
The location of temporary and permanent vegetative and storm water
management qualitative control measures.
G.
An anticipated starting and completion date of the various stages
of land disturbing activities and the expected date the final stabilization
will be completed.
H.
A determination that no lowest floor elevation of any structure is
below the 100-year plus one (1) foot flood elevation.
I.
Storm water management plans shall include designation of all easements
needed for inspection and maintenance of the drainage system and storm
water management facilities. As a minimum, easements shall have the
following characteristics.
1.
Adequate access to all portions of the drainage system and structures.
2.
Sufficient land area for maintenance equipment and personnel
to adequately and efficiently maintain the system with a minimum of
ten (10) feet along both sides of all drainage ways, streams, channels,
etc., and around the perimeter of all detention basins, or sufficient
land area for equipment access for maintenance of all storm water
management facilities. This distance shall be measured from the top
of the bank or toe of the dam, whichever is applicable.
3.
Restrictions on the easements shall include prohibiting all
fences and structures which would interfere with access to the easement
areas and/or the maintenance function of the drainage system.
J.
To improve the aesthetic aspects of the drainage system, a landscape
plan for all portions of the drainage system shall be part of the
storm water management plan. This landscape plan shall address the
following:
1.
Tree saving and planting plan.
2.
Types of vegetation that will be used for stream bank stabilization,
erosion control, sediment control, aesthetics and water quality improvement
along with a time frame for applying the vegetation.
3.
Any special requirements related to the landscaping of the drainage
system and efforts necessary to preserve the natural aspects of the
drainage system.
K.
Open detention basins visible to the public shall be incorporated
into the design as an attractive amenity or focal point in the site
design.
L.
To improve the water quality aspects of the drainage system, the
storm water management plan shall include best management practices
to control the water quality of the runoff during the land disturbing
activities and during the life of the development. This requirement
is in addition to the requirements of the MDNR NPDES.
M.
The storm water management plan shall include all engineering calculations
needed to design the system and associated facilities, including hydrologic
analysis, pre- and post-development velocities, peak rates of discharge,
inlet sites and capacities, and inflow and outflow hydrographs of
storm water runoff at all existing and proposed points of discharge
from the site.
N.
Description of site conditions around points of all surface water
discharge, including vegetation and method of flow conveyance from
the land disturbing activity.
O.
Construction and design details of the storm water management facilities.
[Ord. No. 2772 §1, 5-20-2002; Ord.
No. 3637, 3-20-2023]
The minimum storm water control requirements shall provide measures
necessary to accomplish the following:
Install storm water management facilities to limit the 10- and
100-year developed peak discharge rates to pre-developed peak discharge
rates. The design of these facilities shall be based on procedures
contained in the Storm Water Management Design Manual or as approved
by the City Engineer.
[Ord. No. 2772 §1, 5-20-2002]
A.
Storm
water management facilities may include both structural and non-structural
elements. Design shall be in accordance with the Storm Water Management
Design Manual, as amended, or as specified herein. Natural swales
and other natural runoff conduits shall be retained where practicable.
B.
For
all storm water management facilities, a hydrologic-hydraulic analysis
shall be done showing how the drainage system will perform with and
without the development and how the proposed facilities will function.
Existing land use data shall be taken from the most recent aerial
photography, field checked and updated; future land uses may be obtained
from the Community Development Department.
1.
Storm water detention facilities shall be designed to detain storm
water runoff for the development only. Runoff from tributary areas
upstream of the facility shall be calculated for future conditions;
the detention facility shall be designed to safely pass this flow
without detaining it.
2.
Evaluation of existing storm water management facilities, either
upstream or downstream of the site, shall be done assuming fully developed
conditions for the watershed.
C.
Where
additional storm water management facilities are required to satisfy
the minimum control requirements, the following measures are examples
of what may be used:
D.
Where
detention structures are used, designs which consolidate these facilities
into a limited number of large structures will be preferred over designs
which utilize a large number of small structures.
E.
Storm
water management plans can be rejected by the City Engineer if they
incorporate structures and facilities that will demand considerable
maintenance, will be difficult to maintain, or utilize numerous small
structures if other alternatives are physically possible.
F.
The
storm water management facilities within the City (including both
public and private portions) will be designed to the same engineering
and technical criteria and standards as outlined in the Storm Water
Management Design Manual or as described herein. The City Engineer's
review will be the same whether the portion of the system will be
under public or private control/ownership.
G.
Erosion
control measures shall be established for any development one (1)
acre or larger. Best Management Practices (BMP) shall be utilized
to reduce downstream effects of sediment-laden runoff.
H.
Maintenance
of private facilities shall be described in the plans and shall be
the responsibility of the owner. Failure of owner to maintain these
facilities shall result in the City taking appropriate action to mitigate
such maintenance problems.
[Ord. No. 2819 §1, 3-17-2003]
A.
This Section establishes the criteria for creating a regional storm water facility and the fee in lieu of on-site detention, as required in Section 415.160, and the procedures to determine qualifications to participate in a regional storm water detention basin.
B.
For
the purposes of this Section, the following terms, phrases, words
and their derivations shall have the meaning given herein. When not
inconsistent with the context, words used in the present tense include
the future, words used in the plural include the singular, and words
used in the singular include the plural. The word "shall", as used herein, is not merely directory but is considered mandatory.
1.
On-site detention means storm water storage facilities for and within
a development property as computed in accordance with the applicable
provisions contained herein and approved by the City Engineer.
2.
Regional detention means off-site centralized storm water storage
facilities planned and designed to accommodate runoff from several
developments or sub-watershed drainage areas and with a controlled
release rate in accordance with the applicable provisions contained
herein and approved by the City Engineer.
C.
The
City Engineer shall have the authority to establish a regional storm
water detention facility based on land availability, hydrologic characteristics,
topography, development, hazard mitigation, watershed conditions,
benefit cost and any other criteria deemed appropriate.
D.
It shall be the duty of the City Engineer to determine if a proposed development will qualify for participation in a regional detention basin in lieu of constructing on-site detention. Participation shall only be approved/required when it has been determined that allowing non-detained runoff from the proposed development does not have an adverse impact on the watershed. The impact shall be determined by the City Engineer after submittal and approval of the final storm water management plan in accordance with Section 415.130 and as certified by a professional engineer.
E.
The
per acre participation fee shall be established by the total cost
of a regional detention basin divided by the total acres of potential
developed area in the watershed.
1.
The total cost of a regional detention basin shall include, but is
not be limited to, the following: land acquisition, appraisals, legal
costs, other easements, permits, administration, engineering, inspections,
surveys, construction and maintenance.
2.
The City Engineer shall utilize the Comprehensive Plan to determine
the potential developed area in a watershed.
3.
Each year beginning January 1, 2004, the City Engineer shall adjust
the participation fee to reflect contemporary pricing and the construction
cost shall be adjusted using the construction cost index. Any adjustment
to the participation fee, including supporting calculations, shall
be filed with the City Clerk.
4.
The participation fee shall be paid prior to the issuance of building
permits.
F.
The
participation fee collected shall be designated for regional storm
water detention and shall be used for or applied to the construction
and maintenance of a regional detention basin and expenses incidental
thereto.
G.
The
decision of the City Engineer regarding participation cannot be appealed
to the Board of Zoning Adjustments.
H.
Request
for participation shall be made to the City Engineer on an application
form provided by the Public Works Department which shall include the
final storm water management plan.
[Ord. No. 2772 §1, 5-20-2002; Ord.
No. 3637, 3-20-2023]
Following are the criteria related to using storm water management
facilities for water quality purposes.
A.
A storm
water management plan will be required for the construction of all
ponds, lakes or reservoirs.
B.
When
ponds are used for water quality protection, the ponds shall be designed
as both quantity and quality control structures. Sediment storage
volume shall be calculated considering the clean out and maintenance
schedules specified by the designer during the land disturbing activity.
Sediment storage volumes may be predicted by the Universal Soil Loss
Equation or methods acceptable to the City Engineer.
C.
Storm
water runoff and drainage to a single outlet from land disturbing
activities which disturb ten (10) acres or more shall be controlled
during the land disturbing activity by a sediment basin where sufficient
space and other factors allow these controls to be used until the
final inspection. The sediment basin shall be designed and constructed
to accommodate the anticipated sediment loading from the land disturbing
activity and meet a removal efficiency of eighty percent (80%) suspended
solids or 0.5 ML/L peak settable solids concentration, whichever is
less. The outfall device or system design shall take into account
the total drainage area flowing through the disturbed area draining
to the basin.
D.
Other
practices may be acceptable to the City Engineer if they achieve an
equivalent removal efficiency of eighty percent (80%) for suspended
solids or five-tenths (0.5) ML/L peak settable solids concentration,
whichever is less. The efficiency shall be calculated for disturbed
conditions for the 10-year twenty-four (24) hour design storm event.
