knightsen town community services district (ktcsd)

Knightsen Town Community Services District (KTCSD)

PROPOSED STORM WATER PROJECTS – INITIAL REVIEW

UPDATED FOR MAY 2, 2019 KTCSD MEETING

Step-by-Step Review1. Tonight is initial review.

2. Background & Scope of Storm Water Projects

3. Project Definitions

4. Proposed Project Overview

5. High level walkthrough of 7 proposed projects and descriptions

6. Comments – general and specific to each project

7. Next steps after tonight

2

Background & Proposed Projects Scope In January 2017, KTCSD contracted with Environmental Science Associates

(ESA) to develop a Knightsen Storm Water Resources Plan.

Scope of Plan included:

1.Develop conceptual designs for storm water management projects along railroad alignment & within East Bay Regional Park Wetlands property.

2.Update sizing estimates for culverts and drainage ditches to reflect updated runoff estimates.

3.Update portions of previous assessments to reflect how new developments in Brentwood (that don’t drain into Marsh Creek) effect runoff into Knightsen.

4.Provide cost estimates for implementation (design, permitting, construction) of storm drain improvements and storm water management facilities.

5.Document results of the above that would be suitable to apply for Prop 1 grant funding.

3

Definitions – What is a Culvert?

4

A tunnel in various shapes (that carries a stream or open drain

under roads, driveways, railroad tracks, etc. Common types:

CMP is Corrugated Metal Pipe (very common). Lasts at least

50 yrs.

RCP – Reinforced Concrete Pipes. Concrete with reinforcing

material, typically rebar. Considered highly reliable/cost-effective,

and therefore widely used. Lasts 70-100 yrs.

HDPE – High Density Polyethylene Pipe. Plastic material

engineered to be strong enough to use in place of concrete or

metal pipes, but light enough to be more easily transported and

installed. HDPE is chemically inert, so it can be used to convey

water, gas, wastewater, and even hazardous materials. Lasts 50-

100 yrs.

Definitions – What is a Culvert?

5

While pipe culverts are most common. There are

several types:

1. Pipe – round shape

2. Box culvert - rectangular shape, usually

concrete. Not useful in dry periods. Used to

dispose of rain water.

3. Pipe Arch Culvert - half circle shaped culverts,

used for heavier flows, but flow should be

stable. Fish & sewage don’t get caught.

4. Arch Culvert – similar to pipe arch, but has a

bottom floor.

5. Bridge culvert – used for canals or rivers and

road bridges, surface laid on top.

1

2

3 4

55

Definitions – What is a Bioswale?

6

A vegetated, shallow, landscaped

depression designed to capture, treat,

and infiltrate stormwater runoff as it

moves downstream. They slow down the

speed of runoff while recharging

groundwater table.

They have a slight slope to move water

along the surface to allow sediments and

pollutants to settle out.

Different from a ditch. Ditches collect and

move water away as soon as possible.

Definitions – What is an Infiltration Basin?

7

Shallow, artificial pond or depression

designed to store runoff on the surface

and allow it to gradually infiltrate into soil.

Infiltration basins stay dry, except in

heavy rainfalls.

Has gently sloping sides.

Less effective in areas with:

high groundwater levels, compacted/clay

soils, high levels of sediment in storm

water.

Definitions – What is a Seasonal Wetland?

8

Seasonal wetlands are areas that form during

the wettest time of the year which can dry and

disappear with seasonal change.

They are present when water from rain or

flooding oversaturates the soil.

Definitions – More Terms

9

Term Definition

BMP Best Management Practices – Environmental Protection Agency (EPA)

defines stormwater BMPs as "methods that have been determined to be

most effective, practical means of preventing or reducing pollution from

nonpoint sources."

Biofilter A pollution filtering method where water can flow through dense vegetation

(such as a swale or basin) to clean the water.

HMS

Subbasin

HMS = Hydrologic Modeling System software. CC County Flood Control

uses software program designed by US Army Corp of Engineers.

Subbasin refers to a “watershed” defined by longitude, latitude and other

hydrology characteristics needed to run and create a model.

https://www.contracosta.ca.gov/DocumentCenter/View/3956/2018-03-06-

HEC-HMS-Guidance-for-CCCo?bidId=

https://www.contracosta.ca.gov/DocumentCenter/View/3956/2018-03-06-HEC-HMS-Guidance-for-CCCo?bidId

7 Proposed

Projects

were

identified

10

Projects 1-4 are

interdependent

(water flows from

1 to 2 to 3 to 4).

Projects 5-7 each

have separate

entry points into

East Bay Regional

Park (Wetlands

Restoration

Project)

Project Revisions as of April 4, 2019On 4/4/19, ESA Consultant, Mark Lindley sent the following revisions:

Identified project elements essential to the BASE PROJECT and other elements as OPTIONAL. Some examples:

Listed “optional” elements include extended lengths of ditches which may not be absolutely essential.

Identified many driveway culverts now as OPTIONAL elements of these projects.

Downsized many of his roadway culvert recommendations (e.g. 30 inch culverts reduced to 24 inch culverts; 24 inch culverts reduced to 18 inch) to reduce costs.

Updated costs for each element.

Attempted to prioritize the seven projects.

11

Project #1:

Curlew

Connex

Infiltration

Basin

Retrofit

12

N = New

E = Existing

1

2

34

5

Project # 1: Curlew Connex Infiltration Basin Retrofit

13

Delta Road heading towards

Peach Lane/Curlew Connex

Delta Road @ Peach Lane

New Ditch

New Ditch

(OPTIONAL) Dig new 1,420 foot long ditch along south side of Delta Road and

install new 18 inch culverts at existing driveways and at Peach Lane. Ditch 3ft base

width and 3 ½ feet deep, $20 per linear foot = $28,000. Replacement of culverts on

Delta (+ culverts along Curlew Connex, next page) = $148,000.


14

Delta Road

Delta Road @ Peach Lane

New Ditch

Curlew Connex

Culvert

(OPTIONAL) Dig new 550 foot long ditch along the west side of Curlew Connex and install

new 18 inch culverts at existing driveways. Ditch 3ft base width, 3 ½ ft deep, $20 per linear

foot = $11,000. (BASE PROJECT) Install two new 24 inch culverts across Delta Road and

across Curlew Connex to route water to the infiltration basin by the church. $66,000.

New Ditch

Culvert


15

Culvert and

ditch into

Church Basin

Delta Road @ Church Basin

(BASE PROJECT) Install new 100 foot ditch at Delta Road and Curlew Connex, 3ft

base width, 4ft deep, $26 per linear foot = $3,000. (BASE PROJECT) Improve the

infiltration basin by amending topsoil and revegetating with native plants to improve

water quality treatment and infiltration, 2 ½ acres = $11,000. (OPTIONAL) an

additional 0.7 acres = an additional $3,000.


16

Culvert

New Ditch

(Project #2)

(BASE PROJECT) Install a new basin outlet with a drop inlet outfitted with a flow

control orifice and a new 24 inch culvert across Delta Road. $45,000.

(BASE PROJECT) Install new 1,375 foot Ditch to flow water from the infiltration basin

to Project #2. 3ft base width, 3-5ft deep, $41 per linear foot. $57,000.

Install 24 inch culvert at Knightsen Avenue. $33,000.

NOTE 500 FEET OF DITCH AND THE CULVERT WERE PREVIOUSLY INCLUDED

IN PROJECT #2.

$395,000 construction estimate only

(permitting, ongoing operation/maintenance, and administration,

not included)

18

Project #1: Curlew Connex Infiltration Basin - Construction Costs

REVISED BY ESA on 4/4/19



not included)

19

Project #1: Curlew Connex Infiltration Basin - Construction Costs

Original Costs Provided by ESA on 3/7/19

Project # 1: Curlew Connex Infiltration Basin Retrofit -

Comments

1. Project assumes church basin collects/conveys storm water from neighboring roads/parcels, but approved plans for church did not provide for water to be conveyed in to basin from neighboring properties.

20


Comments2. Project provides for ditch improvements along

Delta Road west past Peach Tree Lane. Are there drainage concerns in this area?

3. Public works’ Capital Improvement Preservation Program (CRIPP). Does future road widening impact project?

21


Comments

4. Will county add ditches when it widens roads?

5. Who will be responsible for maintaining & monitoring Delta Rd basin?

6. Does the high water table impact the ability of the ditch to convey water?

22

Project #2:

Knightsen Ave

Bioswale

Stormwater

from #1 Flows

into Project #2

23

N = New

E = Existing

1

2

3

4

1

5

1

24

Culvert

New Ditch

(Project #2)

Project # 2: Knightsen Ave Bioswale

(BASE PROJECT) Improve existing 180 foot ditch (through downtown), 6ft base

width, 5ft deep, $58 per linear foot = $11,000. Replace 24 inch culvert crossing

Delta Road. $47,000. Improve existing 1,150 feet ditch along Knightsen Ave. south

of Delta Road (8ft base width, 4ft deep for 425 linear feet at $29 per linear foot =

$13,000. 12ft base width, 4ft deep for 725 linear feet at $60 per linear foot =

$44,000).

New Ditch –

Project #1 Existing

Ditch

25

Culvert

New Ditch

(Project #2)

Bioswale

Location

(approx.)

Project # 2: Knightsen Ave Bioswale

Improve 1,150 feet of existing

ditch Knightsen Ave (425 linear

feet north of culvert and 725

linear feet south of culvert.

Costs on prior screen).

Excavate new 560 foot bioswale

north of Knightsen Ave. between

Knightsen Ave. and the railroad.

$68,000. Install a new 30 inch

culvert at bioswale outlet to

drain in to Project #3 wetlands

basin. $38,000. Hydroseeding

and Planting $11,000.

New Ditch –

Project #1Improve Existing

Ditch – Project

#2

Culvert –

Project #1

Project #2: Knightsen Ave Bioswale - Construction Costs



not included)

27


Project #2: Knightsen Ave Bioswale - Construction Costs



not included)

28


Project #2: Knightsen Ave Bioswale - Comments1. Memo on 4/4/17 from CC Flood Control to KTCSD noted:

29

Given this, can Project #2 even accept water from Project #1?

If Project #1 and Project #2 cannot be linked does that impact the need for

Project #2?

“KTCSD would be required to get an easement from

county.”

“According to County’s Real Property Division, easement

wording for flood water detention basin within a

transportation ROW might be limited to only flows

generated by the adjacent road and site area. This might

prohibit the KCSD from conveying flows generated west of

Delta Road and Knightsen Avenue intersection.”

Project #2: Knightsen Ave Bioswale - Comments

2. Public works’ CRIPP identified road improvements for Delta Road Widening (Sellers Ave/Byron Highway – III-34) & Knightsen Ave/Eden Plains Road Widening – Delta Rd to Chestnut St – III-40). How does future road widening impact project?

30

Project #2: Knightsen Ave Bioswale - Comments3. Per CC County Public Works Drainage

Responsibilities document, isn’t the county responsible for replacing this damaged culvert? This document also indicates that existing culvert is 18inch CMP culvert, but Project #2 states it is an existing 24in clogged/damaged culvert to be replaced with new 30inch.

4. Project description says “biofilter could be filled to permit widening of Knightsen Ave.” If biofilteris filled what happens to the water? If the biofilter can be filled for road widening, does that draw in to question whether this project is even necessary?

31

OTHER COMMENTS?

Project #2: Knightsen Ave Bioswale - Comments5. How will bioswale on Knightsen Ave affect land including water table that lies

east (opposite) of railroad tracks?

6. Why have a bioswale instead of ditches?

7. Will a bioswale effectively remove contaminants? Have containments been analyzed?

8. How do we (or do we need) to control what water is allowed to enter the system?

32

Project #3:

Eden Plains

Rd

Wetland

Basin

Stormwater

from #2 Flows

into Project #3

33

N = New

E = Existing

1

2

3 4

4

Project # 3: Eden Plains Rd Wetland Basin

34

Culvert

New Ditch

(Project #2)Wetland

Basin Area

(approx.)

Bioswale Project

#4 in distance

(approx.)

(BASE PROJECT) Add new 24 inch culvert across Eden Plains Road which combined

with existing 24 inch culvert doubles the capacity. $33,000. Ditch to treatment 3ft base

width, 4ft deep, 50 linear feet at $33 per linear foot = $2,000. Excavate a new wetlands

basin for water quality treatment between Eden Plains and the railroad. $149,000. Install

a new basin outlet structure with drop outlet and flow control device to empty in to Project

#4 bioswale. $48,000. New ditch to bioswale (Project #4), 6ft base width, 4ft deep, 150

linear feet at $44 per linear foot = $7,000. Hydroseeding and planting, $6,000.

.Ditch and

Culvert

(locations

approx.)

Culvert from

Project #2

Bioswale

Project #3: Eden Plains Rd Wetland Basin - Construction Costs



not included)

36

Old


Project #3: Eden Plains Rd Wetland Basin - Construction Costs



not included)

37


Project #3: Comments1. 4/4/17 Public Works’ Preliminary Review memo to

KTCSD noted – Same questions regarding feasibility and need for projects #3 and #4 if project #2 cannot accept water from project #1.

2. Public works’ CRIPP identified road improvements for Knightsen Avenue/Eden Plains Road Widening (Delta Rd to Chestnut St – III-40). Widening is a result of increased development surrounding Knightsen. How does future road widening impact project (including culvert replacement across Eden Plains Road)?

38

Project #3: Comments3. CC County Public Works Drainage Responsibilities document indicates

existing culvert crossing Eden Plains Rd is 15 inch not 24 inch as stated in Project #3.

39

OTHER COMMENTS????

Project #4:

Railroad

Bioswale &

Infiltration

Basins

Stormwater from

#3 Flows into

Project #4

40

N = New

E = Existing

12

3

4

5

Series of alternating bioswales/treatment

wetland basins (#1,2&3) running along south

side of railroad tracks. Final treatment

wetland basin (#4) up to 700 feet long also

functions as an infiltration basin to increase

water supply/ groundwater recharge in sandy

soils. Existing 30 inch x 18 inch wooden box

culvert (#5) running under the railroad

maintained to promote positive drainage east

under railroad.

Project #4: Construction Costs

$ 214,000 construction estimate only


not included)

42


Project #4: Comments1. 4/4/17 Public Works’ Preliminary Review memo to KTCSD noted – Same

questions regarding feasibility and need for projects #3 and #4 if project #2 cannot accept water from project #1.

2. What happens to the water (if any) that flows out of Project #4 under railroad through existing box culvert?

43

OTHER COMMENTS????

Project #5:

Eagle

Lane

Bioswale

44

N = New

E = Existing

12

3

4

Project # 5: Eagle Lane Bioswale

New Ditch

(Project #2)

(BASE PROJECT) Dig a new east/west ditch along Eagle Lane (west of bend). 3ft

base width, 3ft deep, 770 linear feet at $26 per linear foot = $20,000. (OPTIONAL)

Dig an additional 1,380 linear feet of ditch. $36,000. Install new 18 inch culverts at

driveways. $84,000.

(BASE PROJECT) Dig a north/south ditch along Eagle Lane (south of bend). 6ft

base width, 4ft deep, 570 linear feet at $40 per linear foot = $23,000. (OPTIONAL)

Dig an additional 1,130 linear feet of ditch. $45,000. Install new 24 inch culverts at

driveways. $168,000.

New Ditch

Project # 5: Eagle Lane Bioswale

New Ditch

(Project #2)

(BASE PROJECT) Install two new 24 inch culverts across Eagle Lane routing water to

the Parks wetlands restoration parcel. $78,000. (BASE PROJECT) Construct new 0.9

acre bioswale on Parks restoration parcel to treat water quality flows (Note: bioswale to

be constructed separately as part of wetlands restoration project). Hydroseeding and

planting, $4,000. (OPTIONAL) Construct an additional 1.6 acres of bioswale,

hydroseeding and planting, $7,000.

New

Culverts

Across

Eagle Lane

Bioswale on Park

Wetlands Property

Project #5: Eagle Lane Bioswale - Construction Costs



and bioswale not included)


Project #5: Eagle Lane Bioswale - Construction Costs





Project #5: Comments1. Need to determine if KTCSD has responsibility for construction and

maintenance of bioswale on EBRPD Wetlands property. If yes, what are costs?

50

OTHER COMMENTS????

Project #6:

Byron Hwy at

Ironhorse Rd

Infiltration

Basin and

Bioswale

51

N = New

E = Existing

1

2

46

5

3

52

Project #6 Byron Highway @ Ironhorse Rd Infiltration Basin and

Bioswale

(BASE PROJECT) 1,250ft ditch along Ironhorse Rd. Current estimate $56,000.

Note: this ditch was added with 4/4/2019 revisions.

Ditch along

Byron

Highway

New Culvert

across

Byron

Highway

Ditch down

Ironhorse Rd

53


Bioswale

(BASE PROJECT) Install two new 30 inch culverts across Byron Highway at

Ironhorse Road to route water on to the East Bay Parks wetlands restoration

parcel. $52,000 each, $104,000 total.

Ditch along

Byron

Highway

New Culvert

across

Byron

Highway

54


Bioswale

Construct new infiltration basin and bioswale on East Bay Parks wetlands parcel. (Note: both

constructed as part of wetlands restoration project). Hydroseeding and planting: BASE

PROJECT, 0.9 acres = $4,000. OPTIONAL an additional 2.9 acres = $13,000.

Infiltration Basin Area

with Bioswale extending

east from Basin

55


Bioswale

Block drainage ditch at Mountain View Drive to limit flows

north

56


Bioswale

(OPTIONAL) Improve 2,500 feet of ditch along west side of Byron Highway south of

Ironhorse Road. Replace existing driveway culverts with 30 inch culverts. Ditch

improvements cost $52,000. Replacing 4 culverts costs $56,000.

Existing

Ditch

57


Bioswale

(OPTIONAL) Improve 875 feet of ditch along Byron Highway north of Ironhorse Road.

Replace existing driveway culvert with 24 inch culvert. Ditch improvements cost $12,000.

Driveway culvert costs $12,000.

Existing

Ditch

Project #6: Byron Hwy @ Ironhorse Rd Infiltration Basin and Bioswale - Construction Costs




59






60


Project #6: Comments1. Need to determine if KTCSD has responsibility for construction and

maintenance of infiltration basin and bioswale on EBRPD Wetlands property. If yes, what are costs?

2. Public works’ CRIPP identified road improvements for Byron Highway Widening (Delta Road to Chestnut Street – III-26). How does future road widening impact project?

61

OTHER COMMENTS????

Project #7:

Delta Rd &

Byron Hwy

Bioswale

62

N = New

E = Existing

1

2

3

46

5

63

Project # 7: Delta Road & Byron Hwy Bio Bioswale

(BASE PROJECT) Improve 1,350 feet of ditch along Delta Road east of Byron Highway.

Replace driveway culverts. Ditch improvements $32,000 (Based on 6ft base width, 3-4ft

deep at $23 per linear foot. Driveway culverts $152,000.

Ditch along

Delta Road

east of

Byron

Highway

64


Install two new 30 inch culverts to route water on to East Bay Parks wetlands restoration parcel.

Construct bioswale and seasonal treatment wetlands on East Bay Parks land. (Note, both

constructed as part of wetlands restoration project). Hydroseeding and planting: BASE

PROJECT, 0.9 acres = $4,000; OPTIONAL, an additional 3 acres = $14,000.

Approximate

location of seasonal

wetlands and

bioswale.

65

(NOT SPECIFIED WHETHER BASE OR OPTIONAL)

Remove accumulated sediment from existing 30 inch culvert across Byron

Highway at Delta Road.

No cost estimates provided.

Project #7: Delta Road & Byron Highway Bioswale

Ditch along

Byron Highway

Culvert

66


(OPTIONAL) Improve 1,270 feet of ditch along Byron Highway south of Delta Road.

Replace driveway culverts. Ditch improvements $17,000 (Based on 3ft base width. 3-

4ft deep at $14 per linear foot). Driveway culverts $75,000.

Ditch along

Byron

Highway

67


(OPTIONAL) Improve 4,210 feet of ditch along Delta Road west of Byron Highway and

replace existing driveway and roadway culverts. Ditch improvements $122,000 (based

on 3ft base width, 3-4ft deep at $29 per linear foot). Driveway and roadway culverts

$383,000.

Ditch along

Delta Road

west of

Byron Hwy




bioswale, and seasonal treatment wetland not included)

69Changed drive

way culverts

from 30in to 24in





bioswale, and seasonal treatment wetland not included)

70

Original Costs Provided by ESA on 3/7/19,

but total actually is $936,000

Project #7: Comments

71

1. Public works’ CRIPP identified road improvements for Byron Highway Widening

(Delta Road to Chestnut Street – III-26); AND Delta Road Widening (Byron Highway

to Holland Tract Road – III-33); AND Delta Road Widening (Sellers Avenue to Byron

Highway – III-34). How do future road widenings impact project?

Project #7: Comments

2. Need to determine if KTCSD has responsibility for construction and maintenance of bioswale and seasonal treatment wetlands on EBRPD Wetlands property. If yes, what are costs?

3. Why are the diversion culverts to EBRPD property NOT included in the cost estimate for Project #7? Instead it says, “Implemented by Restoration Project.” (Note: the diversion culverts for projects #5 and #6 are included in those projects cost estimates).

4. Ditch costs vary considerably. 3ft base x 3-4ft deep quoted at both $14 per linear foot and $29 per linear foot. 6ft base x 3-4ft deep quoted at $23 per linear foot?

5. Why did driveway culverts go from 30 inch to 24 inch ($19,000 each to $14,000 each)?

72

OTHER COMMENTS????

KTCSD Proposed Projects - Cost Overview

Project Project Name Old Costs

1 Curlew Connex Infiltration Basin Retrofit $395,000 $375,000

2 Knightsen Ave Bioswale $230,000 $271,000

3 Eden Plains Rd Wetland Basin $245,000 $248,000

4 Railroad Bioswale & Infiltration Basins $214,000 $214,000

5 Eagle Lane Bioswale $340,000 $480,000

6 Byron Hwy @ Ironhorse Rd Infiltration

Basin/Bioswale

$423,000 $294,000

7 Delta Rd & Byron Hwy Bioswale $799,000 $645,000

Total Construction Costs

with 25% contingency,

design, permitting, Cal Env (CEQA) Report

$3,462,500 $2,530,000

$3,812,500

73

DOES NOT include: annual operating, maintenance, admin costs OR

construction of bioswales & culverts on East Bay Regional Park Land

New ESA’s Cost

$4,112,500

General Comments / Questions1. What sources and base year for cost data were used to estimate costs? (Why

are there variations in costs for ditches of the same size?)

2. Projects involve right-of-ways owned and managed by CC Public Works. What are County’s obligations for improving/maintaining these facilities?

3. Missing assumptions – what storm water event are we planning for?

4. Are there economies of scale associated with doing multiple projects at once? Do ESA’s estimated costs already account for them? Conversely, if only certain projects are done, or the projects are not done at once, do costs increase?

5. Which properties derive a direct benefit from each of these projects? Do some of these properties even have a storm water drainage issue?

74

General Comments / Questions6. What are the relative priorities of each of these projects, especially since

projects 1-4 are interdependent?

7. Are the elevations provided current? What source of information was used?

8. Will KTCSD be required to pay for any easements from the County? From East Bay Parks? From private property owners? Etc.

9. CC Public Works’ Capital Improvement Preservation Program (CRIPP) identifies road improvements for widening Knightsen’s roadways. How do these improvements impact these projects?

75

After Construction, What’s Next?

78

Bioswales, wetlands and infiltration

basins have ongoing operations,

maintenance, and monitoring costs.

Site inspections, water testing

Vegetation Maintenance – planting,

replanting, mowing, seeding, clearing,

etc.

Annual Maintenance Costs - % of Construction Costs

79

Table from EPA Publication https://www3.epa.gov/npdes/pubs/usw_d.pdf

Retention Basins

Constructed Wetlands = 3 - 6 %

Infiltration Basin = 1 - 10%

Swale = 5 - 7%

Detention Basin = < 1%

https://www3.epa.gov/npdes/pubs/usw_d.pdf

Cost per Parcel1. 600 parcels in KTCSD

2. Total cost for all projects (Base and Optional) of $4,112,500 divided by 600 parcels = $6,854 per parcel. (Note: cost would be more for developed parcels and less for undeveloped parcels).

3. Assuming ESA costs are accurate, no matching grant funding and zero inflation: Cost spread over five years = $1,371 per year; spread over ten years = $685 per year; spread over 20 years = $343 per year.

4. Does not account for possible costs for flood control projects KTCSD may need to pay for as part of the East Bay Regional Park Wetlands Restoration Project.

5. Does not take into account cost to employ an Operations Manager and other support staff (permanent or contracted).

6. Does not take into account maintenance costs. Assuming maintenance costs are between 5%-10% of construction costs ($173,000/year - $346,000), maintenance will cost between $288 - $577 per parcel, per year.

80

Evaluating KTCSD Potential Projects

According to California Stormwater Best Mgmt Practice (BMP) Handbook following factors:

Cost – does implementing exceed pollution control benefits? Does revenue stream exist for ongoing maintenance?

Public Acceptance – does BMP have public support?

Pollutant Removal – will it remove or control pollutants?

Implementation - compatible with land uses, facilities, or activities in question?

Technical Feasibility - feasible considering soils, geography, water resources, etc.?

81

ESA’s Ranking of Projects

82

Do projects 3, 4, & 7 provide no or minimal flood reduction benefit -- KTCSD’s primary

goal?

Explanation and justification of this ranking needs to be further explained in draft final

report.

Supporting ReferencesItem URL

Fact Sheet describes the final Municipal Separate

Storm Sewer System (MS4) General Permit Remand

Rule, signed by the Administrator, on November 17,

2016.

https://www.epa.gov/sites/production/files/2016-

11/documents/final_rule_fact_sheet_508.pdf

Army Corp of Engineers – Culvert Life Expectancy -

1997

https://www.publications.usace.army.mil/Portals/76/Publications/EngineerMa

nuals/EM_1110-2-2902.pdf

California Stormwater Quality Assn – Stormwater Best

Mgmt Practice Handbook, Municipal

https://www.casqa.org/sites/default/files/BMPHand

books/BMP_Municipal_Complete.pdf

83

https://www.epa.gov/sites/production/files/2016-11/documents/final_rule_fact_sheet_508.pdf

https://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-2902.pdf

knightsen town community services district (ktcsd)

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