2008 City of Bozeman Storm Water Update
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Transcript 2008 City of Bozeman Storm Water Update
2009 City of Bozeman
Storm Water Update
Dustin Johnson, P.E.
Project Engineer
City of Bozeman
2009 City of Bozeman Storm Water
management update
Design
and Development
Phase II and related expenses
Storm Water Masterplan
Storm Water Sampling
City of Bozeman Review Process
Preliminary
Design
City Board Review –
DRC, DRB, Planning
Board, City Commission,
etc.
Infrastructure Review –
City Engineering, DEQ
Approval
Review Criteria
Zoning
Growth Plan
Transportation
Engineering Review
Why are Storm Water facilities
necessary?
Flood
Control
Channel Stability of
Creeks and Rivers
Water Quality
Potential Re-use of
rain water
Storm water Engineering
Pipe sizing and types
Basin Location
Basin sizing
Slope
requirements
Calculation formats
COB Runoff Coefficients
Rainfall Curves
Floodplain Regulations
Types of Storage/Treatment Facilities
Retention
Designed to retain all runoff from a 10 year, 2
hour storm.
Detention
Basins
Basins
Release water through controlled outlet
structure, at no greater than pre-development
runoff.
Retention Basins
Calculations based on the Rational Formula
Q = CiA (cfs)
V = 7200Q (cubic feet)
i for Bozeman 10 year, 2 hour storm always = .41 in/hr
Detention Basins
More
complicated than Retention Basins
Determine Tc, i @ Tc, and Q of predevelopment runoff
Determine Tc and i @ Tc of postdevelopment runoff
Determine maximum storage volume at
various storm lengths for 10 year storm
Determine size of discharge structure
In a perfect world…
Other considerations
Depth
of groundwater
Other surrounding infrastructure
Historic Drainage Patterns
Limited Space
Facilities not built to specifications
Aesthetics
Easements
When things start to go wrong…
Local Examples of Storm Water
Management
The Good
Local Examples of Storm Water
Management
The Bad
NPDES Phase II
National Pollutant Discharge
Elimination System
Federal EPA regulated by Montana
Department of Environmental
Quality
The purpose is to reduce or eliminate
potential storm water pollutants from
reaching water resources such as
streams and lakes.
Who is permitted for Phase II in
Bozeman?
Continued
partnership with MSU and MDT
as co-permittees on MS4 Phase II.
Storm Water Hierarchy
Storm Water in
Bozeman MT
Phase II Permit
Post Construction
Runoff control
City of Bozeman
MDT
MSU
GLWQD
Public Education
UDO edits
Pollution
Prevention
And BMP’s
Public Meetings
And Feedback
Finding funding
Sources
Construction Site
Runoff control
Storm water
Masterplan
Illicit discharge
Detection and
Elimination
Inspection and
Enforcement
Updated Codes
And Regulations
Storm Water
Sampling
Montana Cities implementing
Phase II
Billings & Yellowstone
County
Missoula & Missoula
County
Great Falls and
Cascade County
Butte
Bozeman
Helena
Kalispell
Phase II
6 Minimum Control Measures (MCM)
Public
Education and Outreach
Public Involvement/Participation
Illicit Discharge Detection and Elimination
Construction Site Runoff Control
Post Construction Storm Water
Management
Pollution Prevention and BMP’s
Total Minimum 5 year Direct Costs for
Phase II
$28,000
$49,400
$20,000
$3,100
Public Outreach and
Education
Public Involvement and
Participation
Illicit Discharge Detection
and Elimination
$120,000
$203,500
Construction Site Storm
Water Runoff Control
Post-Construction Storm
Water Management
Total cost of $424,000 for 5 years
Pollution Prevention and
Good Housekeeping for
Municipal Operation
Summary of Direct costs for
Storm Water Maintenance
Activity
Cost
Clean Storm Sewer Facilities and Ditches
$30,731
Repair Storm Sewer System
$8,860
Leaf Cleanup
$32,650
Street Sweeping
$108,624
Miscellaneous
$9,739
TOTAL
$190,604
All costs based on 2005 estimates taken from COB Storm Water Masterplan
Estimated Total Future Storm
Water Costs
Item
Cost
Direct Operational Cost
$191,000
Phase II Implementation
$100,000
Capital Improvements
$200,000
Indirect Costs (20% of total)
$98,000
Total Cost per Year
$589,000
All costs based on 2005 estimates taken from COB Storm Water Masterplan
Where are we today with Phase II
Completed
year four of a five year permit
Required semi-annual storm water
sampling
Continue working with our co-permitees
MSU and MDT
New engineering standards
Updated public information
Completed Storm Water Masterplan
Storm Water Masterplan
Adopted
by City
Commission late 2008
Is available for public
review and use
Masterplan Breakdown
Existing
System Inventory
System Analysis
Policy Evaluation
NPDES Phase II Permit Compliance
Financial Management Evaluation
Recommended Plan
Significant Recommendations of
the Masterplan
Move
forward in establishing funding
source for storm water.
Establish uniform approach to
development submittals.
Continue relying on development-based
storm water management until Phase II
guidelines are more advanced.
Storm Water Sampling
Started
sampling storm
water in Bozeman in
2007.
As with all Cities in
Montana, the results
were mixed.
Too early to get
anything definitive from
one sampling.
Most Recent Sample Results
(Taken 11/13/08)
Permit
Limits
Above
Kagy
Below
Tamarack
Storm
Langhor
Storm
Tamarack
(mg/l)
(mg/l)
(mg/l)
(mg/l)
(mg/l)
TSS
125
12
13
60
322
Oil and Grease
10
ND
ND
4.5
14
Nitrogen (Total)
2
0.8
0.8
0.8
ND
Phosphorus
0.41
0.09
0.07
0.4
0.91
Zinc
0.21
0.01
ND
0.08
0.18
Lead
0.165
ND
ND
ND
0.03
Copper
0.04
ND
ND
ND
0.03
80
14
11
86
27
COD
Nutrients in Storm water vs.
Waste water effluent
Total Nitrogen
Total Phosphorus
9 mg/L
3 mg/L
Estimated effluent removal
Quality for WRF
expansion (phase I)
7.5 mg/L
1 mg/L
Sample taken 7/25/08 at
storm drain in Tamarack
1.4 mg/L
2.14 mg/L
Sample taken 7/25/08 in Boz.
Creek upstream from Kagy
0.6 mg/L
0.07 mg/L
0.8 mg/L
0.07 mg/L
Estimated current effluent
removal Quality for WWTP
Sample taken 11/13/08 in
Boz. Creek below Tamarack
Going forward from here…
Actively
working with MSU and other
organizations to explore new options
regarding storm water and storm water
education.
Questions/Discussion