HomeMy WebLinkAbout; Bristol Cove Assessment District No. 79-01; Bristol Cove Assessment District No. 79-01; 1979-01-01BRISTOL COVE
ASSESSMENT-DISTRICT:
CARLSBAD^ CALIFORNIA
BEMENT-DAINWOOD-STURGEON
CIVIL ENGINEERS
.JANUARY .1979^
PHASE ONE
I
I
BRISTOL COVE
ASSESSMENT DISTRICT
I. SCOPE
This report outlines the current problems of runoff, erosion, and
deposition associated with the Bristol Cove drainage basin and
incorporates recommendations for construction of facilities to
correct them, with costs and proposed methods of financing.
Prior studies made of this watershed, by the City of Carlsbad and
the engineering firms of Moffatt & Nichol, and Shuirman & Simpson,
were helpful in furnishing maps, topography and hydraulic computa-
tions pertinent to the problem.
II. PROJECT DESCRIPTION " " "--•''
Bristol- Cove Channel on-the" northerly'shore,-of zAgua Hedionda Lagoon
is the point of' drainage concentration from a watershed of_- approxi-
mately 0.7 square miles which is substantially developed.
The area lying between Park Drive and Highland Drive, extending
northerly of the-intersection of Park Drive and Adams Street to
Holiday Manor Subdivision^ is subjected-to-concentrated runoff from
the upper watershed-and suffers-considerable erosion^, -and except"
for a few homes is undeveloped. At the intersection of Park Drive
and Adams Street the waters are collected in a 72" culvert and con-
veyed to a bifurcation chamber near the upper.end of Bristol Cove
Channel where the flow is split. One culvert from the chamber dis-
charges into the upper end of Bristol Cove Channel. The other, a
60" pipe, extends along the easterly shore of the channel to its
outfall in Agua Hedionda Lagoon. This pipe is choked with sediment
and has little hydraulic capability. As a result, most of the silt
laden flood waters enter at the head of the channel where the materi-
al is dropped out.
This report proposes the construction of drainage facilities which
will correct the deposition problem in Bristol Cove. Channel.as well
as allow development of the unimproved" areas in a reasonable manner.
Also included is what is considered to be the most, desirable method
of financing the project.
III. CONSTRUCTION
The Shuirman & Simpson report of 1973 explores alternate methods of
correcting the erosion and deposition problem in Bristol Cove Chan-
nel and the immediate contributory watershed. The report proposed
an interim solution by construction of a series of check dams and
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desilting basins along the path of the drainage. . Although this was
a viable alternative at that time, conditions have changed within
the watershed as explained in Section IV.
The 1973 construction costs of the proposed facilities were estima-
ted at $60,000.00. At present these costs would be $96,000.00.
Also, these facilities would occupy approximately 54,000 square feet
of land area estimated to have a market value of $81,000.00 and cost
approximately $10 , OOO-.-OO- annually-to maintain. The total construct-
ion and maintenance costs of this interim system, over a 10 year
period, would be approximately:
Initial Construction Cost $ 96,000.00
Right-Of-Way Value .81,000.00
Present Worth of Maintenance. . - -
(10,000/yr. for 10 yrs. (a 10%) 61,440.00 - -
Total $238,440.00 '
This does not include design, construction-; engineering^ or inspec.t-r_-
ion costs.
These open basins would be a continuous nuisance and would severely
restrict the development possibilities of adjacent ,land. If main-
tained properly they would solve the siltation problem in Bristol
Cove Channelj but. provide only minimal benefit-to other properties
in the immediate undeveloped area upstream. . '
Further, any funds expended on a temporary solution to the problem
would ultimately be wasted. An underground culvert system, though
more expensive at the outset, is the practical solution and would
offer maximum benefit to those lands on which the streambed lies.
Exhibit "A" indicates the proposed construction of a 48" culvert
and appurtenances, which would extend from the existing 48" pipe in
James Drive to the existing 72" pipe at the intersection of Park
Drive and Adams Street. This culvert would intercept all transverse
drainage facilities and adequately handle the runoff from the water-
shed.
An easement (20' proposed) would be required to protect the facility
between the 48" outfall at James Drive to the point southerly where
the culvert would enter Hillside Drive. From this point to the
southerly connection with the existing 72" RCP at the intersection
of Park Drive and Adams Drive the culvert would occupy street right-
of-way.
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IV. EROSION-DEPOSITION
The entire watershed would theoretically contribute 19,000 cubic
yards of sediment annually according to Shuirman & Simpson's report.
This report was made when a portion of the area easterly of Park
Drive was contributing to the deposition.. Now most of this area,
as well.as that north of Tamarack Avenue, has developed, which has
substantially eliminated erosion in these areas -and the resulting,
downstream deposition.
Practically all of the sediment that is deposited in Bristol Cove
Channel at present is generated in the area between Adams Street
and Holiday Manor, and between Park Drive and Highland Drive. The
highly erodible soils in this area are subjected to damage from
surface runoff to•an-extent but are considerably more vulnerable to
the cutting velocities at the banks of the streambed due to the con-
centrated flows. - ... .
Generally-sediment moves in. a streambed. as—suspended -i-oad in^ the r::
flowing; water and bed load-which rolls-:or:rslides along -the -channel'"
bottom7^ The suspended load-will. vary with- the velocity:-of. the
water,- -Sediment^, sizer, and -.sedimen.tziyi-eld.—.i When these conditions—,
are constant a stream will carry a "balanced" load in that the
sediment content is at its saturation point and the water will
drop out as much material as .it picks up along.a given reach.
Clean water in this respect is erosive, or hungry, and will pick
up more material than it drops out -in an ..attempt to balance-its
load. . Since little material is- brought - down- from the upper water-
shed at present, the cleaner and more erosive water will degrade
this area at a faster rate. The net deposition in Bristol Cove
Channel over the next several years will be somewhat less than if
the entire watershed were contributing but not proportionally since
there is a readily available supply of material in the immediate
area. Eventually, when the local area is depleted or protected,
the erosion-deposition cycle will subside.
Conservatively, an average of 8,000 cubic yards per year of this
material will be displaced and ultimately deposited in the Bristol
Cove Channel unless protected from the high velocities of transient
waters. The proposed culvert system would eliminate this problem.
The erosion generated by local runoff is estimated at only several
hundred cubic yards per year which would dissipate as land develop-
ment progressed.
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v. ESTIMATED COSTS
Item Description Quantity
1. 48" culvert 2,575 L.F.
2. Cleanout or inlet 9 Ea.
3. Connections 2 Ea.
Unit
65.00
1,800.00
500.00
20% Construction Contingencies.:
Total Construction Costs:
Extension
$167,375.00
16,200.00
1,000.00
$184,575.00
36,915.00
$221,490.00
*
**
Incidental Costs
Right-Of-Way Acquisition
Bond Discount" ' '^
Total Project.Costs;
Engineering,-plans, specifications-legal and
bond costs, construction:-surveying. ""These do:
not include-construction inspection-. \
Easement over Assessment Parcels 1 through 5.
44,580.00
7,202.00
5,000.00-
:$ 27 8, 2 72. 00
VI. FINANCING
Because-of the high construction costs and-assessments-a special
assessment district using the Improvement Act of 1911,.Division 7,
of the Streets and Highways Code or the Municipal Improvement Act
of 19l3, Division 12, would be desirable for this project. Using
1911 10-year bonds would allow owners to pay costs over this period
of time at reasonable interest rates taking advantage of tax free
bonds.
The Municipal Improvement Act of 1913 using 1911 Bonds works well
for a project of this size and characteristics. In this procedure,
the City sells the bonds prior to beginning work and progress pay-
ments are made to the contractor. Since this is a cash job for
the contractor it will attract more bidders and reduce costs by
competition.
In the 1911 Act procedure the contractor must finance himself during
the construction period which usually limits the bidder's market.
There are other advantages and disadvantages of one Act over another
which are not pertinent at this time and are not discussed in this
report except to point out that estimated construction costs of the
project are based upon 1913 Act proceedings. These costs would pro-.
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bably increase as much as 10% if the 1911 Act procedure were used
since contractor would havis to finance himself through the work
period
VII. ASSESSMENTS
It is statutory under the Streets and Highways Code that the engi-
neer apportion costs of improvement of a special assessment dis-
trict according to benefits received. Some of the benefits to pro-
perty that would result from this project are:
1. Recovery of land.
2. Preventing inundation of land and buildings.
3. Providing unobstructed access to streets.
4. Allowing construction or widening of streets which serve local
and extended areas. - -
5. Inhibiting, erosion and deposition.
6. Reducing nuisances and.hazards.
To look .at-.this lis.t-:it;.-icould- be-.f.argued..,that--.the--area- of benef it-.-.--„ .
should ex tend--to-the boundaries-of the "watershed:^ but those proper-
ties outside of-the immediate- area, have problems, of their own which
they have-already taken care-of or will: have to face sooner or . later..
To extend the boundaries of an assessment district beyond the area
of direct benefit is sometimes necessary, but,it is impossible to
convince people that they should pay for another person's problem.
In many cases of extended area assessments-the opposition-is over-
whelming and-the-project fails. - -
In this case the problem of where to draw the line is probably the
most difficult-decision to be made.. The more, we study the situation
, the stronger we feel that the Bristol Cove Assessment District should
encompass only those properties, which directly benefit from the im-
provements. These are the parcels niambered 1 through 10 as shown on
Exhibit "A". These properties derive some or all of the benefits
listed above.
This policy appears justified in the case of Parcels 1 through 9
since the existing streambed lies directly on these properties and
under City Ordinance these owners are obligated to dedicate the right-
of-way and construct the ultimate facility over their property as a
condition of development. Therefore, it would not be unreasonable
to assess Parcels 1 through 9 100% of pipe costs along the proposed
alignment over their property. There are many other costs involved
however, and these would have to be absorbed by these owners.
Pipe, appurtenances, right-of-way, and assessment district inciden-
tal costs are estimated at $278,072.00. Spreading this amount over
Parcels 1 through 9 would result in costs of over $120.00 per foot.
These costs are extremely high and some relief must be considered.
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The Bristol Cove Association will derive a substantial benefit
from the project since further siltation in the channel and re-
lated nuisances will be eliminated. At present the upper 300 to
400 feet of channel is unusable for its intended purpose and
approximately an additional 8,000 cubic yards of sediment will
be deposited annually if the unimproved area of the watershed
remains unprotected. Further, documentation indicates that
approximately $10,000.00 to $11,000.00 per year was spent over a
3 year period for dredging the channel.
We recognize that there is litigation pending in this matter and
nothing in this report is intended ,to imply responsibility or..-
liability. The problem will not go away, however, until the ul-
timate facility is constructed and, unless reasonable assess-
ments are possible on Parcels 1 through 9, this may not occur-
To evaluate -the benefits to Parcel-10 -(Bristol Cove Association)
the cost of alternative methods of protecting :the Cove Channel-
from deposition was-reviewed. To alleviate the problem by any
means other than .-.the-proposed . culvertcsystem: would req.uire , as = :.
a minimum,--the ^acquisition of. right-of-way-rand'- constr.uction - of
check dams, and-desilting basins: along the-rexis ting -.streambed i.-iri;v- --:
These facili.ties, -=as-; similar-ly-proposed "by. -Shuirman -and Simpson-s-----
in 1973, would cost. approximately-$lQO , 000. 00.-- They, would not
be completely effective but, with proper maintenance, would trap
most of the sediment that drops out in the Cove Channel and allow
it to operate as anticipated; as a small boat harbor.
A functional requirement of the pipe system proposed in this re-
port is that ^It-connect-to an existing culvert .at ..the intersection
of Park Drive and Adams Street which discharges into the head-
waters of the "Cove Channel. Bristol Cove Association installed
this system and if it were not existing the proposed 4 8" culvert,
or a facility of equal capacity, would have to be extended to the
Cove Channel at an estimated additional cost of. $25 ,000 ..00.
Giving-credit for this $25,000.00 would result in a $75,000.00 net
assessment to the Bristol Cove Association. This amount could be
assessed in the program to the Association as a unit or spread in-
dividually to the various properties.
Although the majority of the costs of the proposed culvert system
would be borne by the owners of property, when and if it develops,
the City will derive a substantial benefit from the development of
the land that will ensue and the reduction of liability from nui-
sances and hazards. Also, the construction will allow for the
widening of -the westerly side of Park Drive, between Adams Street
and Hillside Drive, by owners, and increased vehicle and pedes-
trian safety throughout the area.
If an extended area was included in the assessment the portion
allocated to the outlying area would be approximately $75,000.00.
It is recommended that the City contribute this amount to elimi-
nate extended area assessment and the following apportionment
makes this assumption.
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APPORTIONMENT OF COSTS
Project Cost
(Section V) . $278,272.00
To Bristol Cove Association $75,000.00
To City , . 75,000.00 - 150,000.00
To Parcels 1 through 9 $128,272.00
Cost to Parcels 1 through 9 = ^2^310?^ = $55.53 per foot of culvert
along ultimate alignment, which owners are normally obligated to
construct. This footage is adjusted over several parcels where the
ultimate alignment differs substantially from the existing stream-
bed location-. - . .- .
A summary-of- proposed'assessments- is as • follows: -• - •
Assessment Estimated
Parcel No." - Owner • ; . Assessment-
1 Diversified Financial Systems ,^$15,548.00
2 James E. & Betty Giusto
Jolie Areu, Sylvia -Partida $43,035.00
3 Thomas J. & Marie S. Racciatti $ 2,777.00
4 Spencer & Laura Smith $ 3,054.00
5 Spencer & Laura Smith $ 3,887.00
6 Gurt E. Aagre - c/o Walter Perry $12,772.00
7 Edward C. & Mary L. Moore $17,769.00
8 Opal V. Law $18,880.00
9 Jeffrey & Susan L. Blankenship
Larry & Dorothy Howard $10,550.00
10 Bristol Cove Association $75,000.00
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As the proposed culvert alignment differs substantially from the
route of the existing streambed over Parcels 1 through 9, this
project is not dependent upon replacement of material in the
eroded areas of the contributory watershed, nor is it dependent
upon removal of sediment from Bristol Cove Channel.
Approximately 25,000 cubic yards of material would be required
to fill and dress up the eroded channel areas between Holiday
Manor Subdivision and Adams Street. This could be accomplished
by either of the below described methods or any combination of
the two:
1. A scraper operation obtaining fill material from the imme-
diate area. This would be the most economical method cost-
ing approximately $1.50 per cubic yard or $37,500.00. This
would require. comp.lete-..cooperation .from the owners and unre-
stricted access. This would best be done when the total site
is to be graded for ultimate -^development.
2. Importing •material-:f irom other sites. Dependingr-upon---the .
availability--and hau-l-distance.>-s:this.: would cost... as-,-much-.as .:•-
$4.00 per-.cubic yard, .complete, in place., .or-near ; $100:, OOO. 00 .--
This also would require-cooperation of- ownersand-working-e-^-:"T;--:-.-r
easements over their properties.
If the sediment in the upper 450 feet of Bristol Cove Channel
were removed to -the original graded contours approximately 12,0 00
cubic yards of wet material-would be obtained.- This excavation
could extend to: the common line of Lots 24-,and_25,-rrequiring re-.:
moval and replacement of boat dock facilities in the area of work-
to do the job properly. This material could be used-for -fill -in
the eroded areas if found suitable, and probably would not create
a salinity problem if placed in the lower portion of the fill. The
volume after shrinkage and its suitability will require further
investigation however.
It could be taken out by dragline at a cost of $1.00 to $1.50 per
cubic yard exclusive of dock removal and replacement costs. To
haul and place this material would cost approximately an additional
$2.00 per cubic yard. Drying or mixing would be necessary and a
considerable amount.of shrinkage could be expected.
If filling and dressing up the eroded channel areas in Parcels 1
through 9 were included in the project the- following -additional
costs would accrue directly to Parcels 1 through 9 according to
volumetric proportions:
Method 1. Scraper Operation
25,000 cy. .@ 1.50 per cubic yard = $37,500.00
Increase in- Assessment District
incidentals costs - 8%. = 3,000.00
$40,500.00 .
•8-
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Method 2. Import
25,000 cy. @ 4.00 per cubic yard = $100,000.00
Increase in Assessment District
incidentals costs - 8% 8,000.00
$108,000.00
If the Cove Channel was excavated in this project all costs of
excavation and removal would be assessed directly to the Bristol
Cove Association. If the material from the Cove were placed in
the eroded channel areas upstream the Association would receive
a credit towards their assessment generally for the amount that
it would cost the owners of Parcels 1 through 9 to import material
from another source.
In order to avoid any guess work in the final analysis, the con-
tract documents could- specify.-.alternate-bids. for. use of Cove
material versus outside-material.
The work, as outlined in-the basic-project/ -would take-place in - -
street-.right-of--^way -or easements -.purchased. for^.cons.truction and •-
ultimate, .protectionrrof-.the proposed; culverts system. - This, expan- . -
sion would , require, excessive-encroachment oh-private-property:,.-
voluntaryHCOoperation---from-.the.--owners -and-probably-.-:-s.pecif ie-:deir-—-..
tails of the work that is to take"place on their land. Although "
the benefits are apparent, 100% cooperation in Assessment District
proceedings is often difficult to obtain.
A case -might be made that shifting material from the .;Cove Channel
to the eroded area-.of "r.the upper, watershed was- impor-tant to the
project, however, the validity of extensive work on private pro-
perty in a Special Assessment District proceeding is questionable.
Complete restoration of the eroded areas would be the optimum
solution but would require excessive work out of the public right-
of-way. For these reasons we feel that this project should in-
clude only those items of work listed in Section V.
The succeeding pages of'this report identify the parcels, owner-
ships, and assessment data;
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ASSESSMENT TO PARCEL
#1
ASSESSOR'S PARCEL NO:
OWNER:
207-022-6
Diversified Financial Systems
ASSESSED LAND VALUE;
ASSESSED IMPROVEMENTS VALUE;
AREA:
ASSESSMENT;
RIGHT-OF-WAY CREDIT:
NET ASSESSMENT;
$18,125.00
- 0 -
4.85 acres
*280' X 55.53
1,500 X 0.30
$15,548.00
- 450.00
$15,098.00
* Footage over property adjusted since ultimate alignment differs
substantially from existing streambed alignment.
-10-
ASSESSMENT TO DISTRICT
#2
ASSESSOR'S PARCEL NO:
OWNER:
207-022-8
James E. & Betty Giusto
Jolie Areu, Sylvia Partida
ASSESSED LAND VALUE;
ASSESSED IMPROVEMENTS VALUE
AREA:
ASSESSMENT;
RIGHT-OF-WAY CREDIT;
NET ASSESSMENT:
$13,950.00
$2,900.00
4.2 acres
775' X 55.53
15,500 X 0.30
$43,035.00
- 4,650.00
$38,385.00
•11-
ASSESSMENT TO DISTRICT
#3
ASSESSOR'S PARCEL NO:
OWNER:
207-022-10
Thomas J. & Marie S. Racciatti
ASSESSED LAND VALUE:
ASSESSED IMPROVEMENTS VALUE;
AREA:
ASSESSMENT:
RIGHT-OF-WAY CREDIT:
NET ASSESSMENT;
$1,450.00
- 0 -
10,018 sq. ft.
50' X 55.53
1,000 X 0.30
$2,777.00
- 300.00
$2,477.00
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ASSESSMENT TO DISTRICT
#4
ASSESSOR'S PARCEL NO:
OWNER:
207-022-11
Spencer & Laura Smith
ASSESSED LAND VALUE:
ASSESSED IMPROVEMENTS VALUE:
AREA:
ASSESSMENT;
RIGHT-OF-WAY CREDIT:
NET ASSESSMENT:
$1,325.00
- 0 -
11,000 sq. ft.
55' X 55.53
1,100 X 0.30
$3,054.00
- 330.00
$2,724.00
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ASSESSMENT TO PARCEL
#5
ASSESSOR'S PARCEL NO:
OWNER:
207-022-12
Spencer & Laura Smith
ASSESSED LAND VALUE:
ASSESSED IMPROVEMENTS VALUE;
AREA:
ASSESSMENT:
RIGHT-OF-WAY CREDIT:
NET ASSESSMENT:
$1,325.00 -
- 0 -
11,000 sq. ft.
*70' X 55.53
1,900 X 0.30
$3,887.00
- 570.00
$3,317.00
* Footage over property adjusted since ultimate alignment differs
substantially from existing streambed alignment.
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ASSESSMENT TO PARCEL
#6
ASSESSOR'S PARCEL NO:
OWNER:
206-160-13
Curt E. Aagre
c/o Walter Perry
ASSESSED LAND VALUE:
ASSESSED IMPROVEMENTS VALUE;
$7,000.00
$2,550.00
AREA: 1.59 acres
ASSESSMENT; *230' X 55.53 $12,772.00
RIGHT-OF-WAY CREDIT: - 0 -
NET ASSESSMENT: $12,77.2.00
* Footage over property adjusted since ultimate alignment differs
substantially from existing streambed alignment.
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ASSESSMENT TO DISTRICT
#7
ASSESSOR'S PARCEL NO;
OWNER:
206-192-1
Edward C. & Mary L. Moore
ASSESSED LAND VALUE:
ASSESSED IMPROVEMENTS VALUE;
AREA:
ASSESSMENT:
RIGHT-OF-WAY CREDIT:
NET ASSESSMENT:
$13,275.00
$2,325.00
3.38 acres
320' X 55.53 $17,769.00
- 0 -
$17,769.00
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ASSESSMENT TO DISTRICT
#8
ASSESSOR'S PARCEL NO;
OWNER:
206-192-2
Opal V. Law
ASSESSED LAND VALUE:
ASSESSED IMPROVEMENTS VALUE;
AREA:
ASSESSMENT:
$9,875.00
_: . 0 -
3.28 acres
340' X 55.53 $18,880.00
RIGHT-OF-WAY CREDIT: - 0 -
NET ASSESSMENT; $18,880.00
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ASSESSMENT TO DISTRICT
. #9
ASSESSOR'S PARCEL NO;
OWNER:
206-192-3
Jeffrey & Susan L. Blankenship
Larry & Dorothy Howard
ASSESSED LAND VALUE: $10,650.00
ASSESSED IMPROVEMENTS VALUE; - 0 -
AREA:
ASSESSMENT:
2.73 acres
190' X 55.53 $10,550.00
RIGHT-OF-WAY CREDIT: - 0 -
NET ASSESSMENT: $10,550.00
•18- .
ASSESSMENT TO PARCEL
#10
OWNER: Bristol Cove Association
AREA - HOMESITES;
AREA - CHANNEL:
10.4 acres
4.7 acres
TOTAL ASSESSMENT: CSee Section VII) $75,000.00
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