HomeMy WebLinkAboutA002 - Council Action Form dated September 22, 2015 DATE: 09-22-15
COUNCIL ACTION FORM
REQUEST: PRELIMINARY PLAT FOR HAYDEN'S CROSSING
CONSERVATION SUBDIVISION
BACKGROUND:
Hunziker Land Development Company owns a 12-acre parcel at 5400 Grant Avenue
between Ada Hayden Heritage Park on the east and Grant Avenue on the west. The
site is just over a '/4 mile (1,500 feet) south of 190th Street. (See Attachment A -
Location Map.) The owner proposes the development of a residential subdivision to be
known as Hayden's Crossing and is requesting approval of a Preliminary Plat. The City
annexed this land in December, 2013, and approved a rezoning request from
Agriculture to Suburban Residential Low Density (FS-RL) with a Master Plan on August
25, 2015 (See Attachment B - Zoning). A complete analysis of the proposed
preliminary plat is included in the attached addendum.
The rezoning of the site in August, 2015, included a Master Plan (See Attachment C -
Master Plan) and Zoning Agreement defining the general arrangement of uses and
conditions for development of the site. The master plan allows for single family
development and identifies conservation areas. Zoning Agreement states that: 1) The
Developer is responsible for frontage and intersection access improvements at the time
of subdivision; 2) There is to be a single pedestrian access from the subdivision into
Ada Hayden Heritage Park at the location shown on the Master Plan, and 3) The site is
to include a 30-foot wide buffer of undevelopable open space to be located between the
developed lots of Hayden's Crossing and Ada Hayden Heritage Park, shown on the
Master Plan as "Open Space." Staff finds that the Preliminary Plat is consistent with the
approved Master Plan and Zoning Agreement.
Ames Conservation Subdivision standards are part of Chapter 23 of the Municipal
Code. The intent of the standards is to protect the quality of water in Ada Hayden
Lake, protect existing surface drainage systems, promote interconnected
greenways, provide commonly-owned open space and conservation areas, and
protect such areas in perpetuity. Development of this site is the second project to
request approval under the Conservation Subdivision standards of the Ames Municipal
Code.
The proposed subdivision layout and supporting documents satisfactorily address the
subdivision conservation and improvements standards, with the exception of one issue
focused on street connectivity. The proposed Hayden's Crossing layout is designed as
the first half of a loop street that will extend north and return back to Grant Avenue with
development of the property to the north. The loop street's design will ultimately be the
only street connection through the neighborhood. The design exceeds block length
goals of 600 foot intersections and, while not a dead end street, will appear to exceed
the 1,320 length once it is extended back to Grant. The developer has included a trail
connection to break up the length of the street and believes that a second street
connection is not needed and that the loop design avoids a long cul-de-sac.
The private trail through the common area is a unique proposal by the developer in lieu
of including a cross street. The Preliminary Plat shows a shared driveway as the link to
a 10-foot stormwater maintenance access and trail facility. The Preliminary Plat shows a
five-foot walk then running parallel to the driveway and connecting to the street and
sidewalks (Attachment L). The developer desires to only build the shared driveway and
allowed for pedestrian access without a separated sidewalk (Attachment M). Staff does
not support this proposal of providing no separate sidewalk connection. Staff supports
Exhibit L which clearly delineates the path for pedestrians and ensures there are no
obstructions of the areas with the driveway.
Planning and Zoning Commission Recommendation. On September 2, 2015, the
Commission considered the Preliminary Plat for Hayden's Crossing. The Commission
reviewed the overall design and the issues of street design described above. Justin
Dodge, representing the Developer for the project, stated that the 5-foot wide pedestrian
walkway, located in a 10-foot easement on Lot 16, is not necessary. Mr. Dodge
believes that the shared driveway for Lots 15 and 16, can easily function as a
continuation of the pedestrian trail. He asserted that pedestrians could use the driveway
as their connection with the trail that passes through Outlot B, since the volume of
vehicular traffic using the driveway will be very low, and will not pose a conflict for
pedestrians using the driveway as a trail.
Another concern expressed at the meeting by the Developer is the shared expense for
left turn lanes required when the Rose Prairie subdivision is developed.
Catherine Scott, 1510 Roosevelt Avenue, asked if it would be desirable to continue the
crushed rock surface as in Ada Hayden Park, or some form of permeable paving
throughout the subdivision, instead of using concrete for trails in the subdivision.
Commission members had concerns about the Developer's proposal to use the
driveway as a continuation of the pedestrian trail, which are summarized as follows:
• How would the homeowners know that their driveways are a public share use path?
• How would those using the pedestrian trail know they are welcome to use the
driveway, as part of the trail, between the houses on Lots 15 and 16?
• How would the public path be demarcated on the driveway to make it clear that the
public has the right, and is invited, to walk through the space?
• It seems dangerous, and awkward, for pedestrians, bikers and vehicles to all use the
shared driveway.
• A separate, distinct sidewalk would be a better long-term option than a single strip of
pavement with markings.
The Commission recommended approval of the Preliminary Plat with the separated
sidewalk as shown in Attachment L by a vote of 5 to 1. This recommendation included
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the condition for the pro rata share for the intersection and support for the separate
sidewalk along the shared driveway as recommended by the Staff. Commissioner Tillo
opposed the motion to recommend approval of the Preliminary Plat by the City Council
because he favors the use of a demarcated pedestrian lane driveway (as shown in
Attachment M) that will serve Lots 15 and 16, while acknowledging that it would be
unusual and could be confusing for people.
ALTERNATIVES:
1. The City Council can approve the Preliminary Plat for Hayden's Crossing at 5400
Grant Avenue with the separate sidewalk along the shared driveway, with the
following condition:
A. That the City Council approve a Developer's Agreement to fund the pro rata
share of costs of future intersection improvements necessary at the
intersection of Grant Avenue and Audubon Drive.
2. The City Council can approve the Preliminary Plat for Hayden's Crossing at 5400
Grant Avenue, with modified conditions.
3. The City Council can deny the Preliminary Plat for Hayden's Crossing at 5400 Grant
Avenue, by finding that the preliminary plat does not meet the requirements of
Section 23.302(3)(b) or Section 23.603 of the Ames Municipal Code and by setting
forth its reasons to disprove or modify the proposed preliminary plat as required by
Section 23.302(4) of the Ames Municipal Code. Code sections are found in
Attachment N—Applicable Subdivision Law.
4. The City Council can defer action on this request to no later than October 2, 2015
and refer it back to City staff and/or the applicant for additional information.
CITY MANAGER'S RECOMMENDED ACTION:
The Hayden's Crossing Preliminary Plat demonstrates how the development will carry
out the low-impact policies and techniques required by the Conservation Subdivision
and will thus protect the quality of surface water flowing into Ada Hayden Lake, as was
envisioned when the park land was acquired.
The Hayden's Crossing Subdivision will carry the native landscaping characteristic of
the park into the residential area up to more than 80% of the lots. It will include an
integrated pedestrian and bicycle path system through and connected to the park's
system. It will also provide sites for 20 new homes in the community.
The Preliminary Plat for Hayden's Crossing is consistent with the approved master plan
and zoning agreement in many respects in terms of general distribution of homes and
the density of development. The access points, circulation system, conservation areas
and open space are also consistent with the Master Plan
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Therefore, it is the recommendation of the City Manager that the City Council act
in accordance with Alternative #1 approving the Preliminary Plat for Hayden's
Crossing at 5400 Grant Avenue with the separated sidewalk connection (as
shown in Attachment L) and a condition to share the cost of the Grant Avenue
and Audubon Drive intersection.
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ADDENDUM
Project Description. The proposed Preliminary Plat (See Attachment G - Proposed
Improvements) includes 20 lots for single-family detached homes and additional outlots
for open space an future development. Individual home lots are typically between 7,000
square feet and 10,000 square feet. All lots meet minimum size requirements, and
frontage requirements for the FS-RL zoning district.
There are five outlots in the proposed subdivision, which total 6.12 acres. Outlots A and
B, which include 4.01 acres, will function as open space with a conservation easement
placed over each outlot. On the Final Plat, Outlots A and B will include public utility and
surface water flowage easements over each entire outlot, and Outlot B will serve as the
location for storm water conveyance, treatment and detention, and include a storm
sewer easement over the entire outlot. Outlot A also serves as open and natural space
for the development with selected trees that are in good condition to be preserved a part
of the amenities of this subdivision (See Attachment J — Natural Resource Inventory).
Outlot A also includes the trail connection to Ada Hayden Park as was agreed upon with
the rezoning Master Plan.
Outlot XX is intended for use as a temporary turn-around for fire trucks, and any other
emergency vehicles, until such time that Audubon Drive is extended beyond the
subdivision boundary to intersect with a street (yet to be platted and constructed) to the
north. Outlots YY and ZZ are reserved for future low density residential development.
The developer owns the adjacent land to the north, but has not sought rezoning and
subdivision approval at this time.
Lot Layout and Density. Density calculations (See Attachment E- Typical Sections &
General Notes) have been based upon subtracting the area of all outlots and private
land in the subdivision that will be dedicated to the city as public street right-of-way for
Audubon Drive and Grant Avenue. With this method of subtracting out the area
reserved for future development, the net density is 5.09 dwelling units per net acre. This
exceeds the minimum required net density of 3.75 dwelling units per net acre of the FS-
RL Zone.
Traffic and Street Connections. Grant Avenue is being rebuilt this fall as a rural
collector street, designed with two travel lanes, curb and gutter, and street lights. The
cost of Grant Road improvements is shared by the City and three development interests
with the aforementioned Assessment District. Completion of Grant Avenue road
improvements will occur by the end of this fall. Site specific access improvements are
part of the individual subdivision review and not incorporated into the basic Grant Road
improvements. This means that individual intersection improvements are the
responsibility of each development as they occur.
It is not known, at this time, where the location of an intersection will be on Grant
Avenue with the Rose Prairie Subdivision on the west side of Grant Avenue across from
this site. If the Grant Avenue/Audubon Drive intersection becomes an access
point for future development west of Grant Avenue, the Developer of this
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subdivision, Hayden's Crossing, will be responsible for a pro rata share of costs
related to turning lane improvements. This responsibility for costs associated with
street improvements and turning lanes needs to be documented in a Development
Agreement entered into between the City and the Developer of Hayden's Crossing.
This is a condition of approval of the Preliminary Plat.
On-site Street Layout/Sidewalks. The developer requests approval of Audubon Drive
as a loop street with an eventual connection back to Grant Avenue to the north with the
future development of the abutting parcel to the north. No additional cross streets are
proposed by the developer. The length of Audubon Drive in this preliminary plat is
approximately 1,100 feet. The developer proposes the trail connection to split the block
length up, as is required by FS-RL zoning for blocks exceeding 660 feet.
The main issue for consideration of the street layout is how the eventual loop street
design meets the City's expectations for connectivity of streets. The FS zoning and the
Subdivision Code standards strive for a block length not to exceed 600 feet and to
ensure that streets do not exceed 1,320 feet and to minimize cul-de-sacs and dead end.
The loop street concept creates one long continuous roadway that exceeds a street
block standard of 1,320 feet, but itself is not a dead end street. The loop street design
is not a common circulation design within Ames, which is more typically curvilinear
blocks with regularly spaced intersections.
In this instance the developer believes the loop street avoids creating an
undesirable public street connection within the proposed lot layout, avoids
additional grading, and it helps to avoid creating a cul-de-sac at the end street.
Staff believes a cross street would normally be a required component of the
subdivision of this type, but in this case the loop road could be found to conform
to the general site design standards of the Subdivision Code. Staff does have
some ongoing concern of how connectivity is viewed in the future with
subdivision proposals that minimize internal connectivity for efficiency. Staff
believes the intent of the Codes is for connectivity principally, balanced with
efficiency in layout.
The street width for the proposed Audubon Drive (See Attachment G — Proposed
Improvements) meets the standard for a local residential street, that is, a 26-foot
pavement width as measured from the back of the curb within a 55-foot right-of-way,
accommodating parking on one side. Audubon Drive will include a 5-foot wide sidewalk
on both sides of the street. The street layout also includes a mid-block crossing for
pedestrians as required by FS-RL zoning when a block face exceeds 600 feet.
Pedestrian Connections. The proposed pedestrian trail is another element of the
subdivision design that establishes an interconnected system of conservation areas and
open space for use by the future residents of Hayden's Crossing. Sidewalks, at a width
of 5 feet will be used along both sides of Audubon Drive, and along the west perimeter
of the subdivision, next to Grant Avenue, to provide connectivity in lieu of additional
trails.
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A pedestrian trail connection is planned with the existing upland trail in the Ada Hayden
Heritage Park. The trail is shown as extending through Outlot A of the subdivision,
crossing Audubon Drive, and extending to the north boundary of Outlot B. The portion
of the trail through the open space in Outlot A will have a crushed rock surface to match
the trail it connects to in Ada Hayden Heritage Park.
Where the trail crosses Lots 15 and 16, a separate concrete walkway is shown on the
Preliminary Plat (5 feet wide) in a 10-foot wide pedestrian easement running along the
east edge of the shared driveway for Lots 15 and 16. The pedestrian trail extends
through the full width of Outlot B as a 10-foot wide concrete walkway, and ends at the
boundary between Outlot B and Outlot ZZ. At the time Outlot ZZ is divided into
additional residential lots, the easements, the walkway and driveway planned for Lots
15 and 16 will be repeated to cross the two new lots, and connect to a street serving
those lots.
There was much discussion at the Planning and Zoning Commission meeting, on
September 2, 2015, concerning the design for vehicular access to Lots 15 and 16, in
combination with pedestrian access through Lot 16, as a continuation of the trail that
crosses through Outlots A and B. Justin Dodge, representing the Developer for the
project, noted that the 5-foot wide pedestrian walkway, located in a 10-foot easement on
Lot 16, is not necessary (See Attachment L — Proposed Trail Connection, As Shown on
the Preliminary Plat). Mr. Dodge stated that the Developer believes the shared
driveway for Lots 15 and 16, can easily function as a continuation of the pedestrian trail.
He asserted that pedestrians could use the driveway as their connection with the trail
that passes through Outlot B, since the volume of vehicular traffic using the driveway
will be very low, and will not pose a conflict for pedestrians using the driveway as a trail.
The Developer asserts that pavement markings could be added to delineate the
pedestrian trail along the east edge of the shared driveway (See Attachment M —
Driveway/Trail Design, As Proposed by the Developer).
Staff has communicated our concerns to the Developer about combining the pedestrian
walkway and the driveway into one surface with pavement markings. It is staff's belief
that the pedestrian walkway needs to be separated from the driveway to clearly
differentiate the path from the driveway as a means to clearly denote the route that
pedestrians and bikers are to follow, as well and to avoid a potential conflict between
people parking on the shared driveway and pedestrian/bikers passing through the
easement. The Developer's proposal use a solid 4-inch white line to demark the
pedestrian path from the driveway appears to be a more temporary solution, without a
plan and commitment for ongoing maintenance of the painted line.
Natural Resource Inventory/Conservation Areas/Open Space/Buffer. The applicant
completed a natural and cultural resources inventory as required by the Conservation
Subdivision standards and no significant native plant communities exist on the site, nor
are there any streams, waterways or dry channels on site. (The Natural Resources
Inventory is available for review at the Planning and Housing Department.) Therefore,
the conservation areas in Hayden's Crossing will be "naturalized" by establishing
native plant communities, which is consistent with the conservation subdivision
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requirements. The Conservation Subdivision Ordinance requires that the combination
of conservation areas and open space comprise at least 25% of the land area in the
subdivision, and be a system of interconnected conservation areas and open space
areas distributed throughout the development, such that a minimum of 80% of
residential lots abut a conservation area, or open space. The proposed plat shows
approximately 33% of the land area in the subdivision to be used as open space, and
more than 80% of lots abut a conservation area/open space, which meets the minimum
standard.
The Master Plan and Preliminary Plat include a conservation area and buffer along a
portion of the subdivision boundary. Outlot A extends at a width of 30 feet along the
east and south boundaries of the subdivision, separating Ada Hayden Heritage Park
from the proposed residential lots. Outlot A also includes a 25-foot buffer width along
Grant Avenue, south of Audubon Drive. Outlot B extends at a width of 25 feet along
Grant Avenue between proposed residential lots and Grant Avenue, as well as between
Outlot ZZ (which is planned for future residences) and Grant Avenue. These areas will
be a planted with a native prairie grass mixture. The Conservation Subdivision
regulations require conservation areas that establish separation between external roads
and residential lots be established and maintained, as a vegetated buffer area, a
minimum of 25 feet in width, planted with native plant materials. Staff supports these
outlot buffer areas, as the Parks and Recreation Department believes that this will
provide better protection against encroachments into the park and will contribute to the
health of the planting area.
The Street Tree and Landscaping Plan (See Attachment H - Street Tree and
Landscaping Plan) portrays these naturalized conservation areas. A draft Conservation
Area Management Plan has been submitted that describes these areas and how they
will be established and maintained. More detail for maintenance operations may be
required during the Final Plat approval process. The Developer will have initial
responsibility for creating the conservation areas and the future homeowner's
association will have long term management responsibilities. (The draft Conservation
Area Management Plan is available for review at the Planning and Housing
Department.)
Stormwater Management. One of the principles of the Conservation Subdivision is to
take the approach of Low Impact Development to design the project. This means the
arrangement of lots, street and stormwater management minimizes mass grading of the
site, minimize impervious areas, and maximize use of natural stormwater treatment
measures. The overall approach to stormwater management provides treatment and
control of the peak runoff rate from the entire site by providing multiple opportunities to
slow the flow of stormwater on the surface and settle out and filter out sediments, a
process called the "treatment train." This system includes surface sheet flow to
collecting basins, directing flow by vegetated swales, settlement areas drained by pipes
and pipe outlets into vegetated swales to carry water to other basins. The system is
designed for this project to take the vast majority of runoff to the centralized stormwater
treatment system before it is released from the site. A small amount of water will sheet
flow to the south into Ada Hayden Park, but they will be controlled to not exceed current
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rates of runoff.
Vital to all of these stormwater management systems is the native prairie vegetation to
be established that will help slow the rate of runoff and facilitate the percolation of water
into the soil for natural filtration and treatment. The proposed open spaces include
substantial areas of native prairie planting (See Attachment H - Street Tree and
Landscaping Plan).
2013 Annexation Agreement. Off-site infrastructure of water, sewer, and road
improvements that support the development are part of the 2013 annexation agreement
for the property. An agreement was approved by owners of this subject property and
other developable land parcels west of Ada Hayden Heritage Park abutting Grant Road,
which established the timing and responsibility for extension of all of the urban
infrastructure necessary to provide city services to the North Growth area as an
assessment district (Grant Avenue paving) and connection districts (sewer and water).
The installation of utilities to serve the new developments along Grant Road, and the
paving of Grant Road north to 190t" Street is underway at this time.
Applicable Law. Laws pertinent to the proposal are described on Attachment N.
Pertinent for the City Council are Sections 23.302(5) and 23.302(6). Requirements for
Ames Conservation Subdivision standards are in Division VI of Chapter 23 Subdivision
Standards of the Municipal Code. Zoning standards for Suburban Residential
development are contained in Article 12 of Chapter 29 of the Municipal Code.
Public Notice. Notice was mailed to property owners within 200 feet of the subject site
and a sign was posted on the subject property. As of this writing, no comments have
been received.
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Attachment L: Proposed Trail Connection
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Attachment M: Driveway/Trail Design
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22
Attachment N: Applicable Subdivision Law
The laws applicable to this Preliminary Plat Subdivision include, but are not limited to,
the following: (verbatim language is shown in italics, other references are paraphrased):
Code of Iowa Chapter 354, Section 8, requires that the governing body shall
determine whether the subdivision conforms to its Land Use Policy Plan.
Ames Municipal Code Chapter 23, Subdivisions, Division I, outlines the general
provisions for subdivisions within the City limits and within two miles of the City limits of
Ames.
Ames Municipal Code Section 23.302(5):
(5) City Council Review of Preliminary Plat: All proposed subdivision plats shall be
submitted to the City Council for review and approval in accordance with these
Regulations. The City Council shall examine the Preliminary Plat, any comments,
recommendations or reports examined or made by the Planning and Zoning
Commission, and such other information as it deems necessary and reasonable
to consider.
Ames Municipal Code Section 23.302(6):
(6) City Council Action on Preliminary Plat.
a. Based upon such examination, the City Council shall determine whether the
Preliminary Plat conforms to relevant and applicable design and
improvement standards in these Regulations, to other City ordinances and
standards, to the City's Land Use Policy Plan and to the City's other duly
adopted plans. In particular, the City Council shall determine whether the
subdivision conforms to minimum levels of service standards set forth in the
Land Use Policy Plan for public infrastructure and shall give due
consideration to the possible burden of the proposed subdivision on public
improvements in determining whether to require the installation of additional
public improvements as a condition for approval.
b. Following such examination and within 30 days of the referral of the
Preliminary Plat and report of recommendations to the City Council by the
Planning and Zoning Commission, the City Council shall approve, approve
subject to conditions, or disapprove the Preliminary Plat. The City Council
shall set forth its reasons for disapproving any Preliminary Plat or for
conditioning its approval of any Preliminary Plat in its official records and
shall provide a written copy of such reasons to the developer.
Ames Municipal Code Chapter 23, Subdivisions, Division IV, establishes
requirements for public improvements and contains design standards.
Ames Municipal Code Chapter 23, Subdivisions, Division VI, establishes
requirements for Conservation Subdivisions, as follows:
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DIVISION VI
CONSERVATION SUBDIVISIONS
23.600. CONSERVATION DEVELOPMENT FOR SUBDIVISIONS
23.601. APPLICABILITY.
Conservation Design Development is an alternative set of design objectives and standards for residential subdivision
development. These objectives and standards can be used as an alternative to common residential subdivision
development in Ames. However,they shall apply to all residential subdivision development in the undeveloped areas
of Ada Hayden Watershed north of Bloomington Road.
(Ord No. 4042, 8-1 U-10)
23.602. INTENT.
The intent of Conservation Design Development is to preserve the existing natural features of the site,to preserve the
natural drainage features and hydrologic characteristics of the landscape, and to reduce the impacts of development on
the landscape;and
(1) To rnainiain and protect in perpetuity Arnes area natural character by preserving these importHrit
landscape elements including but net limited to those areas containing unique and environmentally sensitive natural
features as prairie,woodlands, stream buffers and corridors,drainageways,wetlands, floodplains,ridgetops,steep
slopes, critical species habitat, and by setting them aside from development;
(2) To prornote interconnected greenways and environmental corridors throughout Ames;
(3) To provide commonly-owned open space and conservation areas for passive and/or active
recreational use by residents of the development and, where specified,the larger community;
(4) To permit various means for owning conservation areas,preserved landscape elements,and to
protect such areas from development in perpetuity;
(5) To provide greater flexibility in site dwellings and other development features than would be
permitted by the application of standard use regulations in order to minimize the disturbance of natural landscape
elements and sensitive areas,scenic quality,and overall aesthetic value of the landscape;
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(6) To protect and restore environmentally sensitive areas and biological diversity, minimize
disturbance to existing soils, vegetation, and maintain environmental corridors, and
(7) To preserve significant archaeological sites,historic buildings and their settings.
(Ord No. 4042, 8-10-10)
23.603. GENERAL REQUIREMENTS.
(1) Design and Standards for Residential Lot Layout
(a) All residential units should be in cluster groups unless the site has been designed to
preserve sensitive areas and maintain a stormwater treatment train.
(b) All lots shall take access £rum interior roads.
(c) All separation areas for residential lots along existing roads shall be landscaped in
accordance with the conservation area landscaping requirements in Section 23.603(2)(f).
(d) Eighty percent(80%) of residential lots shall abut a conservation area or open space to
the front or rear. Open space and conservation area across a road shall qualify for this requirement.
(e) Cluster groups shall be located to avoid or mitigate directly disturbing existing native
prairie, woodlands, wetlands and other natural features identified in the site inventory of natural resources.
(2) Site Requirements
(a) Open water areas - A 50-foot native vegetative buffer shall be maintained around open
water areas such as ponds and lakes unless a specific common use area is identified.
(b) Stream buffers- Stream buffers with native vegetation shall be maintained along stream
areas using the following requirements based on stream order:
(i) Strearns exceeding 3`d order and above, the City requires sketches,maps, studies,
engineering reports, tests, profiles, cross-sections, construction plans and specifications to determine adequate buffer
widths.
(ii) Perennial streams (I"and 2"order).The total required stream buffer width is
one hundred (100) feet on each side perpendicular to the waterway measured from the outer wet edge of the channel
during base flows.
(iii) Intermittent streams.'The total required stream buffer width is fifty(50) feet on
each side perpendicular to the water way measured from the centerline of the channel.
(iv) Waterways and/or dry channels that have a contributing drainage area of fifty
(50) acres or greater.The total required stream buffer width is thirty(30) feet on each side perpendicular to the
waterway measured from the centerline of the waterway.
(v) Waterways and/or dry channels with a contributing drainage area of less than 50
acres. The total required stream buffer width is twenty(20)feet on each side perpendicular to the waterway measured
from the centerline of the waterway.
(c) Stormwater management
(i) Minimize the use of storm sewer piping and maximize the use of swales.
(ii) Use curb cuts in lieu of storm sewer intakes when appropriate to divert street
water to a stormwater conveyance or treatment system.
(iii) Sump pump discharge can be discharged into a stormwater conveyance or
treatment system.
(iv) On-site treatment and storage of stormwater generated by the development shall
occur in conservation area if it is consistent with the environmental functions of the conservation area. Individual lot on-
site stormwater management may also be used in conservation subdivisions in conjunction with open space and
conservation area management of stormwater.
(v) Include detailed design information for the stormwater management practices
following the design information provided in the Iowa Stormwater Management Manual. The stormwater treatment train
approach shall be used where appropriate to capture, treat and release stormwater.
(d) Shared use paths, sidewalks, and driveways
(i) An accessible and interconnected shared use path system shall be developed to
connect residential areas with open space/conservatiun areas within or adjacent to the site.
(ii) Sidewalks shall only be required on one side of streets;however, all lots shall
have direct access to sidewalks or the pathway system.
(iii) Typical driveway approach sections, Chapter 7 of SUDAS specifications, shall
be used.
(e) Conservation Area Requirements
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(i) The conservation area shall be designated as a Conservation Easement as
detailed in the definition section of this ordinance.
(ii) Applicants must provide an explanation of the conservation area objectives
achieved with their proposed development and identify the percentage of the total development area that this area
occupies.
(iii) All conservation areas shall be part of a larger continuous and integrated system
except for conservation areas that are naturally isolated from other conservation areas on or near the site.For the purposes
of this section, continuous shall be defined as either physically touching or located across a public right-of-way, for
exarnple, nn opposite sides of an internal road.
(iv) Conservation areas,in accordance with the Conservation Area Management and
Ownership outlined in Section 23.605, shall protect site features identified in the site natural resources inventory
Section 23.604 (1) and analysis as having particular value in preserving and/or restoring the natural character and
conserving natural resources in compliance with the intent of this ordinance and consistent with the goals and
objectives of this ordinance.
(v) Healthy natural features such as woodlands,prairie,wetlands,and streambanks shall
generally be maintained in their natural condition, if recommended by a professional with pertinent qualifications,the
Municipal Engineer may authorize a modification to improve the natural features' appearance or restore the overall
condition and natural processes, in compliance with an approved management plan, as described in Section 23.605.
(vi) All wetlands,floodways, and/or identified wildlife habitat areas shall be contained
in conservation areas.
(vii) Conservation areas and open space shall be distributed throughout the development
and combined shall comprise at least twenty-five(25)percent of the total area of the subdivision.An area comprised of
conservation areas and open space greater than twenty-five percent of the total area of the subdivision may be required
if necessary to maintain health features such as woodlands,prairie,wetlands and streambanks in their natural condition
as provided in 23.603(2)(v).
(viii) Safe and convenient pedestrian access and access easements sufficient for
maintenance vehicles shall be provided to conservation areas.
(f) Landscaping for Conservation Subdivisions -A landscaping plan shall be prepared that
identifies all proposed landscaping and conforms to the following:
(i) The preservation of existing native,non-invasive vegetation as identified in the
natural resources inventory Section 23.604(1) as being in good condition and of good quality shall generally be
preferred to the installation of new plant material.
(i i) Mass grading of sites shall be minimized in order to preserve the natural features
of the site.
(iii) Within all required separation areas between residential lots and external roads and
site boundaries, existing woodlands with desirable tree species shall be retained.
(iv) All new landscaping in conservation areas to be installed and existing native
vegetation to be preserved shall be protected through conservation easement. Dative landscaping shall be installed
according to the guidelines provided in the Iowa Stormwater Management Manual Section 2E-6.
(v) Trees of native species as indicated by the Iowa Department of Natural Resources
and approved by the City shall be planted along internal roads within Cluster groups in a total amount equivalent to the
standard subdivision requirements. 'frees may be planted,but are not required, along internal roads passing through
conservation areas.
(v i) Informal, irregular,or natural arrangement is required for newly planted trees to
avoid the urban appearance that regular spacing may evoke.
(vii) Trees shall be located so as not to interfere with the installation and maintenance
of utilities, shared use paths, or sidewalks that may parallel the road.
(viii) Within all conservation areas, separation between external roads and residential
lots,a vegetated buffer area at least 25 feet in width shall be maintained or established. Where no natural trees andlor
shrubs exist, native plant materials shall he planted.
(ix) Conservation areas required to meet Section 23,603(1)(d),shall be planted using
native species to enhance privacy and a natural appearance.
(x) Required buffers around wetlands,all water bodies and drainageways must be
naturally vegetated or planted with native plant species appropriate to the surrounding landscape.
(xi) Buffers consisting of an informal,irregular or natural arrangement of native plant
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species, combined with infrequent or prescriptive mowing are required to create a low-maintenance, naturalized
landscape.
(xii) In addition to the above, land management practices minimizing the impact of
nutrients shall be used and demonstrated in Ada Hayden Watershcd;minimal fertilization of lawns including the use of
phosphorus-free fertilizers is recommended.
(Ord No. 4042, 8-10-10)
23.604. APPLICATION PROCEDURE.
In addition to the standard subdivision application requi rein ents,an inventory and mapping of natural resources shall be
conducted prior to the initial submittal.
(1) Inventory and Mapping of Natural Resources, An inventory of natural resources of the proposed
development site shall be conducted by experts in the field such as biologists, ecologists,soil scientists,hydrologists,
geologists or those credentialed in a manner acceptable to the Municipal Engineer and must be submitted with the
conservation subdivision application. The inventory must.include,but is not limited to the following information mapped
at a scale of no less than one inch equals 50 feet:
(a) Topographic contours at 2-foot intervals.
(b) United States Department of Agriculture,Natural Resource Conservation Service soil type
locations and identification of soil type characteristics such as percolation rates, suitability for infiltration-based
stormwater management practices, hydric soils, depth to water table, and suitability for wastewater disposal systems if
applicable.
(c) Hydrologic characteristics,including surface water bodies,floodplains,groundwater recharge
and discharge areas, wetlands,natural swales,drainage ways,and slopes 10% or greater.
(d) Land cover on the site including but not limited to prairie, woodland, forest,wetland and
general cover type(pasture,woodland,etc.),and stand alone trees with a caliper of more than 24]inches measured four
feet off the ground. The inventory shall include comments on the health and condition of the natural resources.
(e) Known critical habitat areas for rare,threatened or endangered species using existing
documented inventories.
(f) Cultural resources shall be identified by a brief description of'historic character of buildings
and strictures, historically important landscapes,and archeological features using a review of existing, documented
inventories.
(2) Education and Outreach Plan for the Development. An educational plan shall be developed and
distributed to all perspective lot owners that describes the characteristics of the conservation subdivision including the
development concept,conservation areas management practices that will be used to manage these areas,and benefits of
the natural features. They shall also include information on lawn care strategies that reduce nutrient and pesticide inputs
and pollution to local water bodies. Lot owners shall be made aware of the wildlife aspects of a conservation subdivision.
Deer,birds, and other animals and insects will be attracted to the natural areas.
(Ord. No. 4042, 8-10-10)
23.605. CONSERVATION AREA MANAGEMENT AND OWNERSHIP.
(1) Conservation Area Management Plan. Every conservation subdivision must include a plan that
provides evidence of a means to properly manage the conservation areas and open space areas in perpetuity through a
conservation easement for conservation areas or common ownership for open space areas and evidence of the long-term
means to properly manage and maintain all common facilities, including any stormwater facilities. The plan shall be
approved by the Municipal Engineer prior to plat approval.
(a) A conservation area management plan shall be submitted with the following components
during the following approval stages;
(2) Preliminary Plat:
(a) Include a conservation area management plan specifically focusing on the
long-term management of conservation areas. The conservation area management plan shall include a narrative,based
on the site analysis required in Section 23.604(l),describing;
W Existing conditions including all natural,cultural,historic,and scenic elements in
the landscape.
(ii) The proposed completed condition for each conservation area: and the measures
proposed for achieving the end state.
(iii) Proposed restoration measures, including; measures for
correcting increasingly destructive conditions, such as erosion, and measures for restoring habitats, ecosystems, and
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