Transcript Wastewater Collection Options for Lakota Beach Area Sub

Wastewater Collection Options
for
Lakota Beach Area Sub-Basin
Special Meeting June 27, 2001
John Bowman
Lakehaven Utility District
(253) 946-5401
Goal of Meeting
• Provide information on Wastewater
Collection Options
• Provide cost estimates
• Provide information on how a project can
start and what it means to the property
owners
• Answer Questions
Area of Interest
DRAFT Lakota Beach Area
Total Area: ~105 Acres
Property Area: ~80 Acres
Tax Lots: ~135
Wastewater Collection Options
• Gravity Sewer System
• Pressure Sewer System
• Others (not considered viable)
–Vacuum Sewer System
–STEP, Septic Tank Effluent Pumps
–Small Diameter Gravity
•Cost Components:
–Infrastructure (Utility Owned, Public Facility)
–Private Facilities (Homeowner Owned)
–Fees and Charges
Gravity Sewer System Facilities
• Typical for most areas
• 4” Gravity Side Sewer pipe from Building to 6” Sewer
Stub near property line (Private Facility)
• 6” Sewer Stub pipe from property to Gravity Main in street
(Public Facility)
• Gravity Main flows to the treatment plant or a Central
Pump Station that moves flows over hills through
pressurized-mains toward the Treatment Plant
• For Lakota Beach Area, Central Pump Station is needed
DRAFT Lakota Beach Area
GRAVITY SEWER SYSTEM
Pump Station
Gravity Main
Force Main
Pressure Sewer System
• Alternative Sewer System (Low Pressure <50 psi)
• Short 4” Gravity flow from Building to Small Grinder
Pump, usually near building (Private Facility)
• Pressurized slurry from Pump moves through a small 1-1/4”
Side Sewer (Private Facility) to an equally sized Pressure
Sewer Stub near the property line (Public Facility)
• Pressurized flow continues into pressure main ( Public
Facility, usually 2” to 4” in diameter) in the Right-of-Way to
a Gravity System or Treatment Plant
• For Lakota Beach Area, some to Treatment Plant, some to
nearby gravity
DRAFT Lakota Beach Area
PRESSURE SEWER SYSTEM
Pressure Main
Has an Option been chosen for
this Area?
• NO
• Typically new developments are required to
provide gravity type service where available
• Alternatives are considered based on cost
on environmental issues
• A selection will have to be made once a
project is proposed
Gravity Sewer System with Pump Station
(for LBA)
• Pros
– Most home would not have mechanical components for
the home owners to maintain (some still need to pump)
– If zoning densities increased, gravity systems typically
have more inherent capacity for additional flow
– Only Central Pump Station affected by power outages
(on-site generator is assumed)
Gravity Sewer System with Pump Station
(for LBA)
• Cons
– Generally higher cost to install in developed areas
– Gravity Mains would be installed near center of road
(probably need to rebuild roads)
– Gravity Mains would be installed from 6 feet to 18 feet
in depth, Pump Station about 20-25 feet deep
– More disruptive to traffic and access
– 8” Minimum Size (DOE Standard)
– About 25 homes will still need to pump to gravity main
– Pump Station must account for Inflow and Infiltration
potential
Pressure Sewer System
(for LBA)
• Pros
– Less expensive to construct
– Pressure Mains could be installed on the side of roads
(avoiding significant road work)
– Pressure Mains smaller (2”- 4”), installed at about 4
feet in depth
– No Central Pump Station
– Less disruptive to traffic and access
– Lower potential for Inflow and Infiltration
Pressure Sewer System
(for LBA)
• Cons
– All homes would have individual pumps to maintain
– If zoning densities increased, pressure systems typically
have less inherent capacity for additional flow
– Individual home owners affected by power outages
– Size of the mains is more critical. Need to maintain a 2
f/s velocity to keep solids from settling out
Infrastructure Costs
• Gravity Sewer System
– Estimated Cost: $1,860,000
• Pump Station w/Force Main
• Gravity Mains and Stubs to properties
• Road Restoration
• Pressure Sewer System
– Estimated Cost: $ 568,000
• Pressure main and stubs w/restoration
Private Facility Costs
• Gravity Sewer System
– Estimated Cost: $2900 (Range $2000-10,000)
• Assumes 120’ of 4” pipe @ 20$/ft
• Septic Tank Abandonment @ $500
• Pressure Sewer System
– Estimated Cost: $5900 (Range $4000-8000)
• Assumes 120’ of 1-1/4” pipe @ 10$/ft
• Grinder Pump installed @ $4200
• Septic Tank Abandonment @ $500
Connection Fees
• Gravity Sewer System
– Estimated Cost: $2865
• Capital Facility Charge $2720
• Side Sewer Permit $145
• Pressure Sewer System
– Estimated Cost: $3040
• Capital Facility Charge $2720
• Side Sewer Permit $145
• Private Pump Agreement $195
How are these costs paid?
• Infrastructure Costs is typically distributed equitably to
property owners by either:
• Front footage
• Per Lot
• Per Area
• or Zone and Terminus
• Private Facilities Costs belong to individual properties
• Connection Fees are uniform, unless there are more than
one residential unit per property
Example of Total Costs:
Based on Area Charge:
Total Infrastructure Cost / 80 Acres
and assuming a 1/2 Acre Lot
Gravity System
Infrastructure
$
11,625
Private Facilities(1) $
2,900
Connection fees
$
2,865
Total
$
17,390
Pressure System
$
3,550
$
5,900
$
3,040
$
12,490
(1) Will vary widely depending on site condition $2000-10,000
Example of Total Costs:
Based on Per Lot Charge:
Total Infrastructure Cost / 135 Lots
Gravity System
Infrastructure
$
13,778
Private Facilities(1) $
2,900
Connection fees
$
2,865
Total
$
19,543
Pressure System
$
4,207
$
5,900
$
3,040
$
13,147
(1) Will vary widely depending on site condition $2000-10,000
How is a Project Started?
• Utility Local Improvement District (ULID)
– Petition
– Resolution (special circumstances)
• Developer Extension
• Utility Project
ULID
• One or more customers express interest for
sewers in a particular area
• IF there appears to be sufficient interest
(51% or more by land ownership), petitions
are prepared (estimated costs)
• IF the minimum of 51% of the land owner
sign in favor of the formation, the Board
may Certify the petitions and authorize
preliminary design
ULID (continued)
• Formation Hearing (new cost estimates and
boundaries may be redefined as a result)
• IF there is still support for the ULID, the
Board can certify the ULID formation
(Protest can still be filed)
• Project is designed and Bid - ONLY
PUBLIC FACILITIES
• Financing will be reviewed (new cost
estimates) and Construction begins
ULID (continued)
• Final Costs are known and assessed
• Assessment Roll Hearing (Protest can be
filed and allocation method can be revised)
• Legal notice of Assessment (appealable
through supreme court)
• Assessments filed with County Treasurer
for collections
• Assessments begin one year later and
continue for 20 year
ULID (continued)
• Once Public Facilities are in place, Billing
for Sewer service begin, every two months
(regardless of whether properties have
connected)
• Time Frame for ULID Process
– Past experience: 1-1/2 to 3 years
– Pressure Option may be on the shorter side
– Gravity Option maybe on the longer side
Examples of Financing Costs (ULID Assessments):
Based on Per Area Charge:
Annual Assessment:
Gravity
Principal
1/20
Interest Amount
Year Balance* Principal
6%
Due
1
$14,345
$717
$861
$1,578
2
$13,628
$717
$818
$1,535
3
$12,911
$717
$775
$1,492
4
$12,193
$717
$732
$1,449
5
$11,476
$717
$689
$1,406
6
$10,759
$717
$646
$1,363
7
$10,042
$717
$602
$1,320
8
$9,324
$717
$559
$1,277
9
$8,607
$717
$516
$1,234
10
$7,890
$717
$473
$1,191
11
$7,173
$717
$430
$1,148
12
$6,455
$717
$387
$1,105
13
$5,738
$717
$344
$1,062
14
$5,021
$717
$301
$1,018
15
$4,304
$717
$258
$975
16
$3,586
$717
$215
$932
17
$2,869
$717
$172
$889
18
$2,152
$717
$129
$846
19
$1,435
$717
$86
$803
20
$717
$717
$43
$760
* Includes Capital Facilities Charge of $2720
Year
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Pressure
Principal
1/20
Interest Amount
Balance* Principal
6%
Due
$6,270
$314
$376
$690
$5,957
$314
$357
$671
$5,643
$314
$339
$652
$5,330
$314
$320
$633
$5,016
$314
$301
$614
$4,703
$314
$282
$596
$4,389
$314
$263
$577
$4,076
$314
$245
$558
$3,762
$314
$226
$539
$3,449
$314
$207
$520
$3,135
$314
$188
$502
$2,822
$314
$169
$483
$2,508
$314
$150
$464
$2,195
$314
$132
$445
$1,881
$314
$113
$426
$1,568
$314
$94
$408
$1,254
$314
$75
$389
$941
$314
$56
$370
$627
$314
$38
$351
$314
$314
$19
$332
Examples of Initial Costs:
Based on Area Charge And ULID Financing:
Total Infrastructure Cost / 80 Acres
and assuming a 1/2 Acre Lot
Year
0
1
?
?
Items
Gravity
Sewer Bills (1)
$
62
Infrastructure (2)
$
1,578
Private Facilities(3) $
2,900
Connection fees (4) $
145
Total
$
4,685
Pressure
$
62
$
690
$ 5,900
$
340
$ 6,992
(1) $10.38/month or $20.76 bi-monthly (Base Charge Only). Usage fee applies
after connection @ $1.61/ccf of winter water use, typically 16 ccf (2-month)
(2) Decreasing Assessments for 20 years (Includes CFC as part of assesment).
(3) Timing Determined by property owner, cost can vary ($2000-$10,000).
(4) Paid at Time of connection
Developer Extension
• If a large property subdivides to sufficient density
to preclude septic system and needs sewer, the
development could build a portion of the
infrastructure.
• Latecomer Charges could be allocated to
neighboring properties for the portion of the
infrastructure that would benefit them
• Latecomer Charges are paid at the time of
connection
Utility Project
• If there is benefit to the District as a whole to
install sewers in advance, the District could do so.
• Not typical
• Examples:
– Financial - increase customer base
– Environmental benefits
– Opportunity costs (minimize future installation costs)
• prior to new road
• combination with other projects
Area of Interest
DRAFT Lakota Beach Area
Total Area: ~105 Acres
Property Area: ~80 Acres
Tax Lots: ~135