HomeMy WebLinkAboutA002 - Council Action Form dated August 25, 2009 S
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ITEM # 31 a&b
DATE: 08-25-09
COUNCIL ACTION FORM
SUBJECT: SOURCE WATER PROTECTION — ZONING ORDINANCE AND
SUBDIVISION REGULATION TEXT AMENDMENTS
BACKGROUND:
A primary responsibility of the Water and Pollution Control Department is to ensure an
adequate source water supply for the City of Ames and to protect existing wells from
known sources of contamination. Of particular concern is the Southeast Well field (See
attached Map A) and Youth Sports Complex well field (See attached Map B). These
well fields are comprised of a shallow, unconfined alluvial aquifer that has minimal
overburden protecting it from contamination.
Currently, Ames Municipal Code Chapters 23 (Subdivisions) and 29 (Zoning) require all
new developments within the City to meet storm water design requirements that prohibit
an increase in the rate of runoff for 5-year, 10-year, 50-year, and 100-year design storm
events. This is typically accomplished by constructing storm water detention basins.
Iowa Department of Natural Resources (IDNR) separation criteria for new wells require
1 ,000 feet from any lagoons.
Based on past correspondence regarding the Super Wal-Mart site development and
more recent correspondence with IDNR, any storm water detention or bioswale that is
subject to contamination from storm water would be required to meet the same site
separation distance as a lagoon. If an existing well were to fail, the City would not be
allowed to re-drill a replacement well within 1,000 feet of a storm water detention basin.
Super Wal-Mart was required to be platted and storm water quantity requirements were
waived in lieu of storm water quality requirements as agreed upon by the developer and
City staff and approved by City Council. Super Wal-Mart's bioswale is designed to only
take rooftop water and is not considered a potential contaminant source.
Recently, a proposed development at 205 Southeast 5th Street (PETCO, Inc.) came
before the City's Development Review Committee and staff determined that a minor site
plan was required. In order to waive storm water quantity requirements, the developer
applied for a variance from the Zoning Board of Adjustment (ZBA). The ZBA
subsequently denied PETCO's request to waive the requirement. In that instance, the
developer could likely meet storm water quantity requirements but was working
informally with City staff to address concerns over wellhead protection which prevented
storm water detention. Currently, there is nothing in either the zoning code or
subdivision code that addresses the ability to use storm water quality in lieu of storm
water quantity in these areas of concern.
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Examples of water quality based treatment include vegetative filter strips, vegetated
swales, sand filters, porous paving and mechanical separators. The intent of quality-
based treatment is to treat 90% of typical storm events in central Iowa. Quality-based
treatment alternatives will be designed in accordance with the Iowa Stormwater
Management Manual.
Ames water utility customers have invested in our source water infrastructure, and the
purpose of the proposed text amendment is to continue to protect that investment. The
three main goals of the proposed text amendment to Chapters 23 and 29 are as follows:
1. Put protective measures in place based on requirements in the Iowa
Administrative Code [567] Chapter 43 that preserves the ability to re-drill a well in
the same location in the Southeast and Youth Sports Complex Well Fields. (See
attachments for Iowa Administrative Code)
2. Allow coordination between Public Works, Planning & Housing, and Water &
Pollution Control to provide more clarification to developers on storm water
requirements within this area of concern and to allow storm water quality-based
treatment in lieu of storm water quantity-based treatment or some appropriate
combination.
3. Allow development to occur along the South Duff Avenue commercial corridor
without jeopardizing the long-term water supply for the community.
In order to meet these goals, the proposed language for Chapter 23 (Subdivisions) is as
follows (underlined is new text):
Sec 23.401 SITE DESIGN STANDARDS
(8) Water Supply Protection: In order to protect the existing and future source
water supply for the city, the following improvements and uses will be
prohibited within a 1,000-foot distance from any City of Ames drinking water
well located in the Southeast Well Field and Youth Sports Complex Well
Field.
(a) Including, but not limited to, borrow areas, pits, ponds, fountains,
lagoons, storm water detention ponds, and mining operations.
(b) Permanent excavation below existing grade. Temporary excavation
will be allowed for certain purposes. These include, but are not limited
to, footings, basements, and installation of utilities.
In addition, any proposed improvement or use shall not be in violation of
separation criteria for sources of contamination specifically listed in Table A,
567, Iowa Administrative Code section 43.3(7).
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Sec. 23.407 STORM WATER MANAGEMENT
(2) Storm Water Management Design Standards: Storm water management
design shall include grading, facilities or improvements or some combination
thereof, which results in no increase in the rate of runoff when compared to
the undeveloped condition of the area to be subdivided. The rainfall
frequencies that shall be incorporated in the design of the storm water
management system shall include the five year, ten year, 50 year, and 100
year design storm events. In the case of major subdivisions, the calculations
and design of the storm water management system shall be prepared by an
engineer licensed to practice in Iowa.
(a) Exemption. Storm Water Management Design standards do not apply
to any area within a 1 000-foot distance from any City of Ames
drinking water well located in the Southeast Well Field and Youth
Sports Complex Well Field In these specific areas developments will
need to meet requirements for storm water quality-based treatment or
a combination of quantity- and quality-based treatment, as approved
by both the Director of Public Works and the Director of Water and
Pollution Control.
The same language will be utilized in Chapter 29 (Zoning). This will make this
applicable to developments that do not meet the major or minor subdivision criteria.
Sec. 29.406 OFF STREET PARKING
(11) Improvements of Off-Street Parking Areas.
(c) Storm Water Management Design Standards: Storm water management
design shall include grading, facilities or improvements or some combination
thereof which results in no increase in the rate of runoff when compared to
the undeveloped condition of the area to be developed. The rainfall
frequencies that shall be incorporated in the design of the storm water
management system shall include the five year, ten year, 50 year and 100
year design storm events. The calculations and design of the storm water
management system shall be prepared by an engineer licensed to practice in
Iowa.
(Ord. No. 3591, 10-10-00)
(i) Exemption Storm Water Management Design standards do not apply
to any area within a 1 000-foot distance from any City of Ames drinking
water well located in the Southeast Well Field and Youth Sports
Complex Well Field. In these specific areas, developments will need to
meet requirements for storm water quality-based treatment or a
combination of quantity- and quality-based treatment, as approved by
both the Director of Public Works and the Director of Water and
Pollution Control.
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Sec. 29.408 OTHER GENERAL DEVELOPMENT STANDARDS
(8) _Water Supply Protection. In order to protect the existing and future source
water supply for the city, the following improvements and uses will be
prohibited within a 1,000-foot distance from any City of Ames drinking water
well located in the Southeast Well Field and Youth Sports Complex Well
Field.
(a) Including, but not limited to, borrow areas, pits ponds fountains
lagoons, storm water detention ponds, and mining operations.
(b) Permanent excavation below existing grade. Temporary excavation
will be allowed for certain purposes. These include, but are not limited
to, footings, basements, and installation of utilities.
In addition, any proposed improvement or use shall not be in violation of
separation criteria for sources of contamination specifically listed in Table A
567, Iowa Administrative Code section 43.3(7).
One main issue brought up at the Zoning Board of Adjustment meeting was that, by
waiving storm water quantity requirements for the 205 Southeast 5tn Street
development, site flooding downstream on other properties would occur. Staff has
reviewed the merits of this issue and believe that, because of the limited amount of
developable area affected by the proposed ordinance and the proximity to the South
Skunk River, waiving the storm water quantity requirement would have little to no effect
on flooding downstream during minor storm events, which is where detention has the
most effect this close to the floodplain.
Another possible concern is the cost of doing storm water quality based treatment. Staff
is in the beginning stages of requiring both storm water quantity- and quality-based
management for all new developments, so this may become the standard in the near
future for the City of Ames. Thus, the cost of development due to this ordinance
revision would be minimal. Staff believes that the proposed changes are necessary to
protect existing water sources, and that they are consistent with the following objectives
of the Land Use Policy Plan.
Land Use Policy Plan. (See attachments for full text) As evidenced in the Land Use
Policy Plan, Goals for a New Vision, in Chapter 1, Planning Base, Goal #3, (page 16)
objective 3.C., it is the City of Ames' intention to protect aquifers:
"Ames seeks to protect and conserve its water resources for the following
purposes: aquifer protection; water quality protection; user conservation
management; plant and animal life support; water-borne recreation; scenic open
space; and, provision of a long-term/reliable/safe source of water for
human consumption and economic activities."
Also, in Chapter 4, Environmental (page 76), it is the City of Ames' intention to further
develop regulations that are more site specific in protecting aquifers:
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"With respect to water resources, more detailed Storm water Management
Planning on a watershed level will likely be needed. To protect the water
resources, mitigation measures such as storm water quality ponds and other
Best Management Practices will be required as development within a watershed
occurs."
Recommendation of the Planning & Zoning Commission. At its meeting of August
5, 2009, with a vote of 4-0, the Planning and Zoning Commission recommended
approval of the text amendment to Ames Municipal Code Chapters 23 (Subdivisions)
and Chapter 29 (Zoning). Scott Renaud, FOX Engineering, was present on behalf of
four property owners. Mr. Renaud stated that this was a reduction of property rights for
those owners he was representing. The staff explained that the only use that would be
removed under this proposal would be "mining." The other restrictions have to do with
site development excavations. The staff recognized the concern and further explained
that it is fully within the City's authority to protect community resources using
development standards and use restrictions. This approach is consistent with how
many communities protect airport approach paths or require buffering of environmental
resources. Now that new information is available to the City regarding the vulnerability
of the groundwater supply, it is the City's goal to implement protection measures on a
more consistent basis.
Mr. Renaud also stated that the city is basing this proposal on the broad interpretation
of the word "lagoon" as stated by only one IDNR (Iowa Department of Natural
Resources) official. The staff's response was that the City depends on the IDNR as the
authority for permitting new wells and therefore must rely on this person's interpretation.
ALTERNATIVES:
1. The City Council can adopt the text amendments as described above.
2. The City Council can adopt the text amendments described above with
modifications.
3. The City Council can decide not to adopt the proposed text amendments.
4. The City Council can refer this issue to staff for further information.
MANAGER'S RECOMMENDED ACTION:
It is important that the City take appropriate measures to protect the community's
source water supply. Amendments to these two chapters will provide protection of our
current and potential future investments in source water, while at the same time allow
for continued development along the South Duff Avenue commercial corridor. The
proposed ordinance revisions seek a balance between source water protection, storm
water management and continued development. The proposed amendment implements
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the policies of source water protection within the Land Use Policy Plan that have, thus
far, been unclear to the development community.
Therefore, it is the recommendation of the City Manager that the City Council adopt
Alternative No. 1, thereby approving the above text amendments to Ames Municipal
Code Chapters 23 (Subdivisions) and Chapter 29 (Zoning).
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