41-98 OrdinanceRECORD OF ORDINANCES
Dayton Legal Blank Co. Form No. 30043
41-98
Ordinance No.--- -----------------..__ Passed ----- ------ --- - --- - ---- -19-- ---
AN ORDINANCE ACCEPTING THE
STORM WATER MASTER PLAN
AND DECLARING AN EMERGENCY
WHEREAS, City Council has approved the Dublin Community Plan; and
WHEREAS, the land development has significant impact on storm water runoff; and
WHEREAS, the management of storm water flow is important for the health, safety and
comfort of Dublin resident; and
WHEREAS, economic efficiency of land development is realized with consistent, complete
and up-to-date technical information; and
WHEREAS, development of the Storm Water Master Plan was identified as one of the top
priorities by City Council; and
WHEREAS, the Community Development Committee of City Council has reviewed the
Storm Water Master Plan, prepared by Camp, Dresser & McKee of Worthington, Ohio,
dated December, 1997; and
WHEREAS, the Community Development Committee has recommended adoption of the
Storm Water Master Plan by City Council.
NOW, ~HEREFORE, BE IT ORDAINED by Council of the City of Dublin, State of
Ohio of the elected members concurring that:
Section 1. That the document entitled "City of Dublin Storm Water Master Plan" dated
December, 1997, be accepted as the official plan in guiding storm water management in the
City.
Section 2. That this Ordinance be, and the same hereby is, declared to be an emergency
measure for the preservation of the public peace, health and welfare of the residents of this
City, and therefore this Ordinance shall take effect and be in force immediately upon its
passage.
Pass this ~_ day of , 1998.
- Presiding Officer
Attest:
Clerk of Council
Sponsor: Director of Engineering/City Engineer
T RereSy certify th'af copies oT this Ordinances ~b}d pbited iti the
City of Dublin in attordance with Section 71.25 of the Ohio Revised Codb.
f'i'r [lei t of ncil, Du i ,Ohio
G:\OFFICE\WP\COUNCIL\ORD4198. WPD
MEMORANDUM
TO: City Council
FROM: Timothy C. Hansley, City Manager
INITIATED BY: Balbir S. Kindra, Director of Engineering/City Engineer
DATE: Apri127, 1997
SUBJECT: Ordinance No. 41-98 Concerning Acceptance of the Storm Water Master Plan
Attached, please find a copy of the proposed ordinance regarding the subject matter. This report has
been reviewed by the Dublin Community Development Committee. The Committee has
recommended acceptance of this report by City Council.
In January of this year, City Council was provided with copies of the "Executive Summary" of the
Storm Water Master Plan. For your ready reference, attached with this memorandum is another copy.
Acceptance of this plan and companion Storm Water Management Ordinance will permit City staff to
work with the up-to-date, consistent and complete information for developments in each water shed
in the City. Stormwater system information, for the first time, is now available in digital formats for
any engineering firm involved in the Dublin development process. Engineering staff will now be
equipped to guide storm water management in a complete, comprehensive and continued basis to
preserve the quality of life in Dublin.
This Master Plan is an independent document, primarily containing technical information for use
mostly by engineers. However, the accompanying Storm Water Management Ordinance will
establish new policies, procedures and controls. The ordinance will also replace MORPC's Storm
Water Management guidelines.
The Community Development Committee has asked for additional information regarding
"Stormwater Connection Fees", and "Stormwater Impact Fees" for potentially financing, fully or
partially, the City's stormwater infrastructure and enhanced operation and maintenance of the system.
This information is expected to be developed within the next 90 days for presentation to the
Community Development Committee. The Engineering Division staff strongly recommend
acceptance of this report.
Respectfully submitted,
~~~~ s. ~4r~ol,,.N
Balbir S. Kindra, P.E.
Director of Engineering/City Engineer
BSK:jc
;~,,, Attachment
i
E
Executive Summary
The City of Dublin is located in the Columbus, Ohio metropolitan area with
the majority of the City lying in northwestern Franklin County. Portions of
the City are located in southeastern Union County and southwestern Delaware
County. Over the past decade the City of Dublin has been experiencing rapid
developmental growth. This rapid growth has burdened the City's
infrastructure, including its stormwater management system. To properly plan
for and manage growth the City has initiated strategic plans that will identify
future infrastructure needs. This stormwater master plan (SWMP) is one of
these strategic plans.
As development in the City occurred, additions to the City's stormwater
management system (SWMS) were occurring in a piecemeal fashion. That is,
additions to the City's SWMS were occurring in or near the development area;
however, the affect this had on the City's overall stormwater,~tnent
system was difficult to comprehend. The City had„.~e~~~dof`~.~~re the
improvements were occurring, but did nothave a ~rt~~rehensiv~~''~~::_
understanding of its SWMS. Thus, it wsrduous ~~~'#c~#nine 1`t~s~~;.
developments in the Ci ,,;a.~f~e.,the ex'';'::SWA/1`::riAS more rvvfh
occurred; the City expecec~'#e r~5~zth i~i.:WMS.
_..........._ _ ....... ............ P :::......._. __............... ........
Because a~%s'~{#~#iec~~cf~f~;:Ci ~'`'~' tracted with Cam Dresser &
......... ...... .. ... ~'::~. P
McKee (CE3~~;.to ~%eiare`~~~or~r~ter'management plan (SWMP) for the
City. The k;c.Qtt~nents~~tif~the SWMP were identified as follows:
^ Determine the extent of the overall contributory area to the SWMS, as
well as for watersheds and sub-basins within the area
^ Determine the extent of the City's existing SWMS
^ Map the location of the existing SWtiIS and compile the corresponding
system's data into a database such that the location and data for a
specific portion of the system can be readily obtainable
^ Determine how the system performs for existing land use conditions and
if the City's existing performance criteria for the system was being met
^ Develop alternatives and cost estimates for implementing the alternatives
that will allow the system to meet or exceed the City's performance
criteria where performance deficiencies in the system are found
^ Identify potential locations for regional detention facilities
dubswmp.exs I CDM Camp Dresser & l~lcKee
ES-1
Executive Summary
C
dubswmp.exs
^ Develop an overall simulation model of the system such that a
comprehensive understanding of the system will result and that
modifications to the system can be readily accommodated
^ Review the City's existing performance criteria and recommend
improvements to the criteria so system deficiencies are minimized
^ Determine the potential of having to implement water quality features for
stormwater runoff in the near future and, if warranted, recommend
criteria to be implemented to reduce pollutant loads from stormwater
runoff
CDM performed the services to properly address these stormwater master plan
key components. The findings and results of CDM's investigations,
determinations, and evaluations for each of these key components are..
presented below.
Contributory stormwater Runoff Area
The City of Dublin is approximately 20 square mil:~rs~'t~~~. •~~~Tt#ajority of
the drainage in the City is to natural str~ai~s that ~.c~rbutor~~`;the Scioto
River. The Scioto River, which::flows tl~±~u.. the C:3,r:st~~'~"northth
production, and dam construction.
direction, rovides a nar~::~~vest c~,~'~;ithiri'~t:.Ci .The"~ciot
P ty o Rives
d . :;::.state'': _;~;s:::::;;:...
i-
sdeli at
e
,,~ .,.a....:.. ~ur.~`ater ~~~lrs as'c~Te of the ma' r d
gn ..: )o rucking
wat
er
u~:s ~..:~,CoIs;~etro a~%" ~~~~~~~a~a"' The O Shau
........ ....... ... p .;:;:;;::. gnessy
Reservoir'cti~ich`~t~cat~~ti1~~~ot~~~` ver 'ust north f th
o e City of Dublin,
serves as arid;>~Qf t~;ity i~folum$us drinking water storage facilities. Water
from the resf~ows through the City of Dublin to the intake structure for
the City of Ct~fiumbus Dublin Road water treatment plant. The Ohio
Environmental Protection Agency (EPA) classified the Scioto River as impaired
for the river segment located within the City of Dublin. This designation was
given to indicate that the river segment was not attaining aquatic life use
designation as determined by monitored biological and chemical data and/or
nonpoint source survey results. Also for this river segment, the Ohio EPA
indicated that it was impaired by urban nonpoint stormwater runoff, crop
There are 24 major streams that traverse the City of Dublin to their confluence
with the Scioto River. Some of the streams are located entirely within the
City's current boundaries. However, several of these streams have
contributory areas that are outside the City's boundaries. The entire
contributory area of the streams that flow through the City of Dublin is
approximately 35 square miles. Thus, approximately 15 square miles of area
located outside the City of Dublin contribute stormwater runoff to the streams
that flow through the City of Dublin. This contributory area does not include
the Scioto River's contributory area. Figure ES-1 shows the location of the
City of Dublin, the 24 major streams that traverse the City, and the overall
contributory area to the streams.
CDM Camp Dresser & McKee ES-2
Executive Summary
Existing City System
The City's existing stormwater management system is comprised of numerous
physical structures. The physical structures that are representative of the
stormwater management system are collection, conveyance, and storage
structures. Collection structures are catch basins and curb inlets. Conveyance
structures are manholes, junction structures, headwalls, detention basin outlet
structures, pipe tap connections, and open and closed conduits such as
streams, man-made channels, storm sewers and culverts. Storage structures
are detention basins, lakes and depressional areas.
Based on the above information, the SW~1S physical structures were located
with respect to the Franklin County Auditor's Office GIS files and given an
unique identifier. The identifier for each physical system was developed with
the City and is based upon the' City's existing grid system, which is linked to
the State Plane Coordinate System (SPCS).
As each physical system was located, a digital data file for the,;..stre was
created and the available attribute data for the specificp~sics'`ss~em was
put into the digital file. The physical system attritr~ifta inclu~'cortduit
inverts, closed conduit sizes, top of stru.:.elevat~j;e of sure (i.e.,
manhole, catch basin, curb..iz;~,ulvert'~e~t':;and ma~1,-the '''?~f~~ _ and
:~ . tYPe;. ~
cover above a closed cont'~~~tft~uit s''"``'` .'':~t °~" ~ ch~l cross sectional
information,.:€~ ~:;;::stora":e:zu};t#~'}er ava~~~t~e`zQrmafon that was utilized to
create sirs:~ion:;Csdels~f~~`~~~~VMS~~~~'~~ to ether over 19 000 in iv'
........... .............. ...... ........... ~._ g d idual
attribute c~~~filestnt:re c~ted~~~~t~~~~1~~~~ViVIP, including a roximatel 8 600
....... ~ PP Y
closed con~~}ix..aulver~s~~~10;000 nodal structures (catch basins, curb inlets,
manholes, hat~~s.and junction structures), and 450 stream segments.
Watershed Delineations
In order to evaluate the performance of the City's SW1~LS, the 35 square mile
contributory area was disaggregated into watersheds that corresponded with
the streams that flow through the City. These watersheds were then
categorized into three main groups based on their locations within the City.
The three main groups of watersheds are the East, Northwest, and Southwest
Area Watersheds. The East Area Watersheds are those watersheds located east
of the Scioto River and were further subdivided in smaller groups of
watersheds. The four watersheds north of Summitvie~v Road are identified as
the Northeast Area Watersheds, while the nine watersheds directly south of
Summitvie~v Road are identified as the Little East Watersheds. The Northwest
Area Watersheds are those that are located west of the Scioto River and north
of US 33 and SR 161. The Southwest Area Watersheds are those that are
located west of the Scioto River and south of US 33 and SR 161. Those areas
that drain directly to the Scioto River and do not drain into one of the 24
streams previously mentioned have been identified as Unconsolidated Areas.
The Unconsolidated Areas have also been subdivided into the three main
groups and are known as the East, Northwest, and Southwest Unconsolidated
"!"' dubswrt,p.exs ~ CDM Camp Dresser & McKee ES-4
Executive Summary
.~.*
Areas. The list of watersheds in each of these groups and sub-groups is
presented below.
East Arecz Watersheds
Billingsley Creek
Little East
Northwest Area Watersheds Sotithzvest Area Watersheds
South Fork Indian Run
North Fork Indian Run
Monterey Creek
Cosgray Creek
Cramer Creek
Hirth-Woolpert Creek
Thornhill Creek
Brown/Horch Creek
Unconsolidated Areas
Orchard Crest Creek River Forest Creek
Hanna Hills Creek Deer Run
Bait Shop Creek Loch More Creek
Dry Bed Creek Unconsolidated Areas
Tamarisk Creek
Mayapple Creek
Tonti Creek
Wyandot Woods Creek
Dry Creek
Northeast Area
Summitview Creek
Arrowhead Creek
Westbury Road
Trails End Creek
Hard Road (North & South)
Unconsolidated Areas ::;,;;~:>>
or Southwest Area Watershed,
evaluations sections of this SWMP (Volumes 1, 2 and 3).
A stormwater model for each watershed was set up and calibrated such that
the simulation model would be accurately representing the watershed's
drainage system. In order to perform this calibration effort, data obtained
from the City of Dublin and City of Columbus raingauge network and data
gathered from the City and resident interviews were utilized. During the
interview process, CDM obtained from City staff and residents their best
recollection of high water elevations for storm events that were easily
remembered. As a result of these intervie~vs, CDM obtained raingauge data
for three storm events, the July 13, 199?, February 27, 1996 and May 31/June 1,
1997 events. These three events were the most recent storms that were easily
remembered by the interviewees. For the calibration storm events the rainfall
data from the Discovery Boulevard rain gauge was primarily used, as this
gauge provided the most reliable data for the three storm events. The
calibration of the stormwater models are presented in the watershed
"" ' dubswrt,p.exs ~ CDM Camp Dresser & McKee ES-5
Stormwa~er Simulation Models
Executive Summary
Existing System Analysis
~• Once the stormwater model was calibrated, it was then used to simulate the
watershed's SWMS for the following three storm events:
1) the 2-year, 24-hour storm event
(2.70 inches of rainfall);
2 th - ar 24-h u
e 5 ye o r storm event
(3.35 inches of rainfall); and
3) the 100-year, 24-hour storm event
(6.06 inches of rainfall).
The 2-year, 24-hour storm event is a theoretical storm event with a rainfall
magnitude that is expected to be equaled or exceeded once on the average
during any 2-year period. Therefore, during any one-year period, this storm
event has a 50 percent chance of being equaled or exceeded. The;;.ed
.~:::s .:. .. ,::;::
conduit conveyance system is typically designed to conve~r;,ri~~:ithout
surcharging for this event. Through experience, it~ee~n fourit~~'at for
natural streams, the flow in a stream for<t;2-year~i storrent is
contained within the -stream s;:.~ain chaee ~~~hus, t':e'7riodel stte~d "out-
of-bank" .conditions for::. ~><::>~`'';':.;>;:~''<;' .
.~::~e~~...dunn ::.}~e'~~;"`:.ar st~..event, then there is a
hi h otenti.a~~:;:~~r::~trear`bank';:s:vsion `..:<_..,:.;:..<.,;:::::.:::.:. ..
g P .~ . to..<~~;.
.~~
Th
~xn ~t:# .gip ~-~rear~ho ~'" orm event should only be equaled
or exceedet~'ce:;s;~;#he ae~'a a `diin~ 5- ear eriod. Therefore, this
g g Y Y P
storm even~~::~~t~~I_ has a 20 percent chance of being equaled or exceeded
'~`"' during any r~rie=hear period. The 5-year storm was used to determine if the
existing closed conduit system is operating at the City's current design
standard for new drainage systems. In some areas of the City however, the
drainage system was only designed for the 2-year storm event. In these areas,
• surcharging of the closed conduit system is expected for this storm event.
However, in the areas where the more recent design standard has been
imposed, surcharging should not occur unless the system has been undersized.
The rainfall amount of a 100-year, 24-hour storm event should only be equaled
or exceeded once on the average during any 100-year period. Therefore, this
storm event's rainfall has a one percent chance of being equaled or exceeded
during any one-year period. The Federal Emergency. Management Agency
(FEMA) uses this storm event to analyze riverine systems, for the purpose of
establishing floodplains and flood~vays. Most closed conduit conveyance
systems are not designed to convey the 100-year storm event because of cost
constraints. However, conveyance of the 100-year storm's runoff through
surface channels (i.e., overland flow or streets) to a suitable receiving
waterbody is typically provided when the closed conduit system is designed
,,,~,,, ~ for less frequent storm events. This type of stormwater design lessens the
chance for major flooding problems to occur. The results of these storm event
"r. dubswmp.exs CDM Camp Dresser & V1cKee ES-6
Executive Summary
simulations are presented in the watershed evaluations sections (Volumes 1, 2
and 3) of this SWMI'.
Future System Analysis
The analysis of the existing storm sewer system for future conditions assumed
' that all stormwater runoff from future development will be detained and
released as a minimum at current pre-development conditions. Therefore,
under this assumption, existing peak stormwater flows are not exceeded
during post development conditions. Allowable release rates were developed
for each sub-basin so that the City can monitor and guide development and
ensure that this condition is met.
Watershed Evaluation Results
The watershed evaluations were reviewed to determine the effectiveness of the
SWMS to meet the performance criteria for the 2-year, 5-year and 100-year 24
hour storm events. Based on these evaluations, areas were id~z~'t:where
the SWMS did not meet the criteria for these storm ev,e~:~. ';~rther
review of these areas was performed to determine~t~~trtpact to'~ity if
these areas were left unimproved. If a s~}:#icant irr#al im~';'::~":`;was
determined to exist, then it. was:>dentific~;ai~n area'~;COncern a~~~:
im rovemerit alternativ~r''~`~~` '
p .. ._:~luatet~:i;f~~viate?. condition~causin the
` For exam ,~;~;t w~s~flun=~tat`~:~ta' ~"' of the Ci 's existing strea
~: ... ~}~ ty d ms were
flowing ou~;~~-ba~:.f..or th~:..2, year~4-hour storm. This indicates that there was
the potenti`~~~~ereased stream erosion in these locations. It was also found
that this potential erosion will not have a detrimental impact to existing
structures neighboring the streams because the potential erosion will continue
to occur only within the floodplain of the stream. Thus, to address this issue,
it is recommended to only restrict development from the stream's floodplain.
This will allow natural widening of the stream to occur within the floodplain
without affecting neighboring structures.
Another example is for the 5-year 24-hour storm evaluations. In instances
where the closed conduit system was determined to be insufficient to
adequately convey the runoff from this storm (i.e., without the SW1~1S
surcharging above the gutter line invert or edge of pavement), the identified
area was reviewed to determine if there was sufficient conveyance for the
runoff via a roadway or overland flow path to an appropriate runoff receiving
location within the watershed. No improvements were recommended where
sufficient alternative conveyance routes existed. However, where alternative
conveyance routes did not exist, then improvements to the SWl~1S were
recommended.
dubswmp.exs ~ CDM Camp Dresser & McKee ES-7
Executive Summary
Another process that was utilized throughout the SWMP study was resident
interviews. The resident interviews allowed verification of deficiencies where
the SWMS simulation model showed areas as being marginally deficient.
Based on the watershed evaluations and the additional investigations
mentioned above, the SWMS deficiencies shown in Table ES-1 were identified:
Alternatives Evaluations and Recommended
Improvements
Improvement alternatives were evaluated to alleviate the SWMS deficiencies
after the areas of concern were determined. Probable construction and project
cost estimates for implementing the alternatives were also developed. In some
cases, the proposed improvement alternative may address more than one area
of concern. Various references recommend the following considerations for a
public project:
1. Technical feasibility and reliability -the project or ogtio~;:s.t~'be
feasible and reliable (minimize risk) based oz~;.;t*~t~;t~terlln.~y while
solving or relieving as much of the.:lct~flwn pr~infsl as passible.
2. Socio-political acce~ta}~x;;:~::.the `E3`~2~`£#r o ht7~s::~hould be ~e table to
fY ~ :~ P .... P
the public and the r~eltilatory~ agen~zes .. ...
3.
or option should give `a reasonable
public funds that are expended.
4. Enviraerltal~ consistency -the project or option should be consistent
with known environmental goals and facts.
I Based upon these considerations, the following assumptions were made in
evaluating the alternatives:
1. Only the most technically feasible options were considered (e.g., some
feasible options that would be technically difficult to implement were
excluded).
2. Regulatory agency guidelines were incorporated into all options and
potential public reaction was considered.
3. Options were developed based on obtaining protection commensurate
with cost.
4. All options were developed with the intent of improving the
environmental health of the area (particularly in terms of water quality
and wetlands. benefits).
~, dubswmp.exs I CDM Camp Dresser & McKee
ES-8
Executive Summary
Table ES-1
City of Dublin
Stormwater Master Plan
Stormwater Management System (SWMS) Deficiencies
.~.y,
Number of
Number of
Number of
5-year Areas 100 year Areas Maintenance/
Watershed of Concern of Concern Erosion Concerns
Eastern Area Watersheds
Billingsley Creek 0 3 0
Orchard Crest Creek 0 0 0
Hanna Hills Creek p 0 0
Bait Shop Creek 0 1 0
Dry Bed Creek 0 0 0
Tamarisk Creek 0 1 0
May Apple Creek 0 1 ~~ 1
Tonti Creek 0 0 0
Wyandot Woods Creek 0 1 ~ 0
Dry Creek 0 0 0
Summitview Creek 0 ~ ~
Arrowhead Creek 0 ~~~~ ~'
Westbu R
oad
rY
0
.
0
T
rail
s En
d
Cre
ek
0
~'?
0
H
and .
R
oad
No
rth
o
0
H"ar
dR
oa
d..
tt~
'
~
0
'
0
U
neon
s i
~
of
~a:..
~d
<:>3
-
~
~ ~• .
3
_
0
-
~, Eastern Ares~:;~1{~tere<i Suts;~p#s.-
'
'3 13 1
Northwest Are~~~~atersheds
""" South Fork Indian Run 0 0 3
North Fork Indian Run 0 1 1
River Forest Creek 0 0 0
Deer Run 0 1 1
Loch More Creek 0 0 0
Unconsolidated Area 1 0 0
Northwest Area Watershed Subtotals 1 2 5
Southwest Area Watersheds
Monterey Creek 0 1 0
Cosgray Creek 1 ' .1 0
Cramer Creek 0 •=1- ~ 1
Hirth-Woolpert Creek 0 2 1
Thornhill Creek 0 0 0
Brown/Horch Creek 0 0 0
Unconsolidated Area 1 0 0
Southwest Area Watershed Subtotals 2 5 2
City Totals 6 20 g
.r.. dubswmp.exs I CDM Camp Dresser & McKee ES-9
Executive Summary
Based on these considerations, improvement alternatives were recommended
to alleviate the SWMS deficiencies. The estimated probable project cost for
each recommended improvement is presented in Table ES-2 for each
watershed. As this table indicates, there are a total of 20 improvements with
an associated cost of approximately $3,361,000. These recommended
improvements are necessary to alleviate the identified SWMS deficiencies.
Figure ES-2 shows the location of all areas of concern in the City and where
improvements are recommended.
Policies and Procedures Recommendations
During the course of the SWMP study the City's existing policies and
procedures were reviewed to determine their effectiveness to provide adequate
stormwater management activities for the City of Dublin. This assessment
consisted of some or all of the following components:
sser srri+~t of s`iev~""`";'is su`:~:~~;;~:;<;;';;,..~>;:' ~~ 'L
T
he full a ""'`:'~
~t?r~ x...;ut CD.1 s December 1997
1'
Po ici
es `' ~~`~
.,,d, 3'ro~,,.res `.; ;"`';~r~s`e ~'`z findn~~ s of this review are
~ . :. _ g
.presented': the ft~r3vui~ p~ragrap~s
ndards
The primary source of stormwater management regulations and design
standards in 'the City is the Mid-Ohio Regional Planning Commission
(MORPC) Stormwater Design Manual (SDM). This manual was adopted by
ordinance in 1978 to be the official governing document for stormwater
facilities within the City's boundaries. In addition to this manual, the City also
uses the drainage design procedures outlined in the Ohio Department of
Transportation (ODOT) Location and Design Manual Voltcme 2 -Drainage Design
and the provisions located in Chapter 1~1 (Flood Control) of its codified
ordinance.
While the MORPC SDI provided suitable guidance for SWNIS improvements
for the time period when it was prepared, many of'its features need to be
updated to reflect more current storm~vater management concepts and physical
data (i.e., more recent studies that present more recent climatological
conditions, specific design criteria for stormwater management features, such
as side slopes for retention and detention basins, depth of retention basins,
required easement widths to allow for adequate maintenance of the SWMS,
etc.). The MORPC SDVI does not address stormwater quality concerns, which
have become one of the major programs for the United States Environmental
dubswmp.exs I CDM Camp Dresser & McKee ES-10
Executive Summary
dubswmp.exs
Table ES-2
City of Dublin
Stormwater Master Plan
Estimated Probable Project Costs
Probable
Eastern Area Watersheds Improvement Name Project Cost
Billingsley Creek - Resize Three Culverts $816,000
Little East -Riverside Drive Improvements 99,000
- May Apple and Tamarisk Creek
Improvements $149,000
Northeast Area -Northeast Area Improvements $304,000
Unconsolidated Area -Dale Drive Improvements $228,000
- Wendy's/Riverside Drive
• Improvements $121,000
- Martin Road Improvements $343.000
Total Eastern Area Waters hed Probable Project Cost Subtotals $2,060,000
• - s~~~z~~robab/e
Northeast Area Watersheds Improvement Name .::. ~
.
~
~.~ ~s?~3?roiecf Cost
South Fork Indian Run -Stream Improvemer't~'~ri:~
~~
.
No h
rt F r
okln i
d an R
un
::.. r
ea ~~~
~~`
~ ..
;'~
`
..,,,,,itV....
$54,000
Probable
Southwest Area Watersheds Improvement Name Project Cost
Monterey Creek -Stream Improvements Near
Clover Court $18,000
Cosgray Creek -Stonewall Court Improvements $80,000
Shier Rings Road Improvements $189,000
Cramer Creek -Avery Road Ditch Improvements $6,000
Wilcox Road Improvements $61,000
Hirth-Woolpert Creek -Hirth-Woolpert Creek Watershed
Improvements $123,000
Unconsolidated Area -Blazer Parkway/Frantz Road
Improvements 6161.000
Total Southwest Area Watershed Probable Project Cost Subtotals $638,000
Total Probable Project Cost Totals $3,361,000
CDM Camp Dresser & McKee ES-11
REFER TO FIGURE ES-2
CITY OF D UBLIN STORMWA TER MASTER PLAN
RECOMMENDED IMPROVEMENT LOCATIONS ~ PROJECT COSTS
(located behind summary in front pocket)
Executive Summary
r~
,,~,
Because of the above mentioned items it is recommended that the City develop
and implement its own stormwater management ordinance. This ordinance
will strengthen the City's current stormwater management program and allow
the City to effectively administer improvements to its SW1~1S. It will also
allow the City to be proactive in implementing stormwater quality criteria to
reduce pollutants from runoff prior to its release to receiving streams.
SWMS Operations and Maintenance
Operations and maintenance (O&M) includes those activities required to run
the City's stormwater facilities on a daily basis and to keep the drainage
system functioning as designed. Two of the fundamental O&LI policy issues
are who is responsible for maintaining the components of the SWMS and how
often should the various maintenance activities be performed.
^
^
/swales and detention
^ general repair or replacement of drainage facilities not operating
properly.
The City is currently practicing the shared responsibility policy for new
detention basin construction. When there is shared responsibility, the City is
responsible for the functionality and structural integrity of the basin, while the
property owner or homeowners association is responsible for general
maintenance (e.g., mowing, litter, and debris removal).
As development in the City progresses and the SWMS increases in size
proportionally, the need for a routine maintenance. schedule and clear lines of
responsibility will become vital to allow the SWMS to function properly. The
maintenance currently provided by the City is primarily performed on an as
needed basis or in response to a complaint or emergency. Through this
approach, schedules and standards are not known, defined, or coordinated.
Based on a review of the City's current O&_ti1 practices for its SWMS, the
following changes are suggested to the City's current maintenance policies.
..,~ dubswmp.exs ~ CDM Camp Dresser & McKee
ES-13
Executive Summary
1. Detention Basins - To allow basins to function as designed, the City should
continue its current shared responsibility policy and maintain the
components that assure the structural integrity and functionality of the
basin and delegate the general maintenance requirements (i.e., mowing)
to the property owner or homeowner association. It is also
recommended that this policy be retroactive and include all residential
homeowner association detention basins that were installed under a
previous policy. However, for this to happen, two issues will need to be
resolved: liability and ingress/egress.
Privately owned detention basins are currently maintained by the
individual private property owner. CDM does not recommend changing
this current policy; however, CDM does recommend that the City require
the private developer submit detention basin as-built drawings and
provide proof that maintenance of the basin is being performed: This
will confirm whether the detention basin is designed and maintained per
the approved plans. _. _. _...
2. Storm Servers, Culverts Inlets Cat.
Specific schedules and standards
and a maintenance plan .prepares
will need to deter~r.~r~~~i':sting
and future:,maintrice~re~~~rPn
~3.
bt~tignated
etei~~'e City
can rrmeet current
1e if additional
A standard schedule to
streams should be developed so problems and
activities can be identified. It is also
recommended that the City develop and implement maintenance access
(ingress and egress) criteria.
Recommended Maintenance Frequencies & Costs
In order to develop a preliminary stormwater maintenance program for the
City, various programs from around the country were reviewed and combined
with our experience to formulate the following tables that outlines the
activities and suggested frequency ranges for a routine maintenance program.
Based on these recommended frequencies for performing the SWtiIS O&M
activities, annual costs to perform the activities were estimated. Table ES-3
provides the estimated annual cost to perform O&?~I activities for the SWMS
excluding detention basins and Table ES-4 provides the estimated cost to
perform. the O&M activities for detention basins. As these tables show, the
total estimated annual cost to provide the recommended StiVMS O&M
activities is $739,271. As estimated by the City, it is currently spending about
x230,000 per year on SWti1S O&1~1 activities; therefore, the total estimated
additional annual cost to achieve the recommended level of effort is $509,271.
..~.
F dubswmp.exs CDM Camp Dresser & McKee ES-14
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ES-16
Executive Summary
Structural Improvements Implementation
Implementation of the stormwater structural improvements in the City of
Dublin is dependent on the following items:
^ the ability to implement an improvement quickly with minimal cost
impacts to the City;
^ the level of benefit that the improvement will provide to the City's
residents;
^ the ability of the City to fund the improvement; and
^ implementation constraints associated with the improvement.
Based on this prioritization criteria, the recommended structural improvements
are prioritized as follows:
Ranking Structural Improvement
1 Clover Court
2 Forest Run Drive Out£all
3 Avery Road )~:t~~<<::
:;:....
- 4 ;..;...._,
Coffman.Park'~':<<~:
5
:`~:
:;;:;~ ;;.Are.,
~:t ~;
7 l~sid;~rive ~~ ~~ :..: rov~~n
8 D~I':~r~~~~
9 Mar~%`r~"~l~oazi
10 . Blaier Parkway/Frantz Road
11 Brahd Road/Bear Run
12 Stonewall Court
13 Resize Three Culverts
14 Shier Rings Road
15 Hirth-Woolpert Improvements
16 Aryshire Drive
17 Mayapple & Tamarisk Creek
18 Wickline/Limerick Drive
19 Shawan Falls Drive
20 Wilcox Road
Watershed '3~roject Cost
R~Ionter~~r~~€:: 518,000
firth Fdr~~ran Rur~~; 524,000
'~?er Cti.:k •' • • 56,000
:;,a~`~~E;For~s#,~dian Run 518,000
`Noreast Area
5304,000
pastern Unconsolidated 5121,000
Little East 599,000
Eastern Unconsolidated $228,000
Eastern Unconsolidated 5343,000
Southeast Unconsolidated $161,000
North Fork Indian Run $184,000
Cosgray Creek 580,000
Billingsley Creek $816,000
Cosgray Creek $189,000
Hirth-Woolpert 5123,000
Deer Run 5247,000
Tamarisk Creek 5149,000
Northeast Unconsolidated 5136,000
North Fork Indian Run 554,000
Cramer Creek 561,000
Regional Detention Basins
Structural improvements also include the implementation of potential regional
detention basins. As presented in the watershed evaluations, there are six
areas that may be suitable for the construction of regional detention basins.
However, because all potential regional detention basins that were identified in
the watershed evaluations are located at the western jurisdictional boundaries
of the City, which limits their ability to be implemented due to jurisdictional
dubswmp.exs I CDM Camp Dresser & McKee
ES-17
Executive Summary
issues, the regional detention basins are not recommended to be implemented
at this time.
Non-structural Controls
.~
As previously presented, it is recommended that the City develop and
implement its own stormwater management ordinance. This ordinance will
strengthen the City's current stormwater management program and allow the
City to effectively administer improvements to its SWMS: It will also allow the
City to be proactive in implementing stormwater quality criteria to reduce
pollutants from runoff prior to its release to receiving streams.
Funding ,
The City's current annual expenditures for stormwater conveyance system
maintenance and detention basin operation and maintenance (O&~1) activities
is about $230,000. The detention basin O&M activities, which costs the City
about $100,000, consist primarily of mowing the 36 detention facilz~s owned
and operated by the City an average of 14 times per yeac..TInimended
SWMS O&M activities and frequencies increase th#g't'~:~FtI~~' expe~'t±~ure by
about $509,271 for a total annual cost of;9,271. ~~~d;~3~~ion to"~h;annual
expenditure, the Stormwater:.Nlaster Pla~;~:~~s~mmertt~et~`~3~361 OOd:~:'''rth~ f
structura .°~~ o
p :.~~sc~uded~~t ~a`~,; wig:a ital im rovements
:::::,:;:~' .:...:. P P
ro am C.II';:s'£o ro'`s;:;;>~;;,.
P ~ .~,,.:.>:::::~..:::;:::.:.>:,:::. ::~;~,:.:;:a~~~ss the>':~';'``;'"~;s:~?orm~~se~~er s t
infrastruc:€'e`'~stit~rer}~:; >';t;~~s kn~ to ez t
.~ ~ .,~.,,, ;,;..::.::.:.::: s ,the City needs to dedicate
additional?€ids varc3 ~`~rPi~ttr~~rtii~a+o"„"~,,.~,,,
Adequate ft~`~~~ essential to successfully implement and manage a
comprehenstve~~stormwater management program. A funding plan will
specifically empower the City to establish rates or other charges on all real
property- in the City to support the management of the entire drainage system.
Funding mechanisms used for stormwater management programs across the
country are primarily city income taxes, ad valorem taxes and stormwater use
charges.
The current trend for cities with proactive comprehensive stormwater
programs has been toward user fees. The user fee that is recommended for
the City of Dublin to support the implementation of SWti1S improvements and
improved maintenance of the SWMS is the impervious area charge or
stormwater utility. stormwater utilities have been proven to be dedicated, fair
and equitable funding sources for many municipal stormwater programs
across the country. Two municipalities in close proximity to the City of
Dublin that have implemented stormwater utilities are the Cities of Columbus
and Upper Arlington.
~,
dubswmp.exs I CDM Camp Dresser & McKee ES-18
,.,,