City of Plaza, ND - Vision West ND€¦ · City of Plaza, ND Municipal Infrastructure Needs...

City of Plaza, ND

Municipal Infrastructure

Needs Assessment

June 12, 2012 Project made possible by US Dept. of HUD Regional Substantiality Planning Grant

and ND Energy Development Infrastructure and Impact Grant Fund programs

City of Plaza | Infrastructure Needs Assessment 2

Summary of Needs Assessment

The City of Plaza, located in Mountrail County, North Dakota, is experiencing a population increase due

to energy development activities, with current proposed developments expected to increase the City’s

population from an estimated 250 people to 420 people. The infrastructure needs assessment is

intended as a high-level analysis and concept planning effort focused on key short-term infrastructure

needs required to facilitate the anticipated growth and development. Table 1 summarizes the

infrastructure needs assessment, proposed improvements, and costs estimates included within this

report.

TABLE 1 SUMMARY OF INFRASTRUCTURE IMPROVEMENTS AND ESTIMATED COST

DESCRIPTION ESTIMATED COST Water System Improvements Two new groundwater wells and elevated water tank $ 1,781,000 OR Connection to North Prairie Water System and elevated

water tank $ 2,314,000

Wastewater Collection System Improvements Lift station replacement $ 380,000 Wastewater Treatment System Improvements Lagoon system upgrade to 52,000 gpd $ 2,258,000 Street System Improvements Mill and overlay $ 572,000

TOTAL ESTIMATED COST $ 4,991,000 to $5,524,000

Introduction

The Vision West ND initiative was commenced in February 2012 to provide planning and technical

assistance to a rapidly expanding 19-county area in western North Dakota. The primary goals of the

Vision West ND project are to assist communities and counties in the western region of North Dakota

in addressing near-term needs to meet growth management challenges and establish a diversified

economy in the future through the development of local and regional strategic plans.

Rapid population growth is exerting significant pressure on existing municipal water, sewer, and streets

systems and, in some cases, need infrastructure expansion to support continued growth. Participating

communities will receive a high-level infrastructure assessment to identify needs, prioritization of

infrastructure improvements, and opinions of probable costs by a professional engineering team.

Building Communities, Inc. is the lead strategic planner engaged in the Vision West ND initiative and

has subcontracted with Advanced Engineering & Environmental Services (AE2S) to provide technical

expertise on municipal infrastructure.


This report includes brief infrastructure inventory, needs assessment, and opinions of probable costs

for infrastructure improvements for the City of Plaza, North Dakota. The information used to prepare

this assessment for the City of Plaza was compiled by AE2S during an interview with City of Plaza

officials on March 21, 2012.

COMMUNITY OVERVIEW

The City of Plaza is located in the southeast corner of Mountrail County. In 2006, the Parshall Oil Field

was discovered and since that time, intense oil development has occurred in Mountrail County. In

2010, the census recorded the population of Plaza at 171. At that time, the City had 97 utility

connections. Presently, it has approximately 130 connections and the current population is estimated

at 250 people. The K-6 grade school has seen an increase from 30 to 60 students in the last four to six

years.

City of Plaza


CURRENT AND PLANNED DEVELOPMENT

The current average occupancy rate within the City is 1.9 people per housing unit. Presently, there are

known future development plans for an additional 59 residential housing units as indicated below. An

assumption of an additional 30 housing units may be needed to account for future unknown

development plans including RV Parks or campgrounds.

According to City officials, future housing expansion plans that

have been submitted to the City include the following:

Robyn’s Addition (presently under construction) = 25

single family houses

Two eight-plex housing units = 16 units

Three four-plex housing units = 12 units

Six-unit apartment building = 6 units

Temporary housing including RVs and skid housing. The

specific number is unidentified (quoted by City officials as

“numerous”).

The projected total service population of the City is estimated to

increase from the present population of 250 people to as much

as 420 people (approximately double its current population) or

219 residential housing units if the projects listed above are constructed. In addition to the housing

units identified above, the City reported a new laundromat will be built and other types of businesses

such as a loading dock for rail shipping of crude oil, man camp, or RV/mobile home park may be

constructed in the near future. Outside of the City, a tribal oil refinery is planned approximately four

miles away, which most likely will also affect population growth.

A moratorium on growth was adopted by the Plaza City Council in October 2011 until plans for

additional water and sewer capacity are adopted. There are no industrial sales allowed due to a

shortage of water (this includes no water sales to farmers for spray water). Only water sales for

domestic use are allowed.

POTABLE WATER SYSTEM ASSESSMENT AND IMPROVEMENT ALTERNATIVES

Water System Demands

Based on the near-term development information and utilizing a future population estimate of 420

people, the average day domestic water demand is calculated as 100 gallons per day (gpd) per capita


resulting in an estimated water demand of 42,000 gpd. The 100 gallons per capita per day estimate is

is used by Ten States Standards, recommended standards for public water supplies, to predict

domestic water usage in communities where no water meter records exist.

Many small communities also have a substantial irrigation demand that increases the summer water

consumption anywhere from two to as much as four times the winter water usage. A recent report

from nearby Montana indicated the ratio of summer water use to winter water use was 2.25 in

metered rural communities and 2.30 in unmetered rural communities. The national average of summer

use to winter water use on a per capita basis is typically 2.0.

The City does not meter its water customers and it may be appropriate to assume a factor of 2.3 when

comparing summer water use to winter water consumption.

Summer demand = 42,000 gpd x 2.3 = 96,600 gpd

Irrigation demand = 96,600 gpd – 42,000 gpd = 54,600 gpd

It is estimated that winter water consumption patterns occur for about six months of the year, summer

water consumption patterns occur for four months of the year and for two months of the year

irrigation occurs at about half the summer rate. Estimated monthly water consumption is shown Table

2.

The Maximum Day Demand is estimated by applying a peaking factor to the average day demand. This

peaking factor in small communities like Plaza is estimated at 2.5. The corresponding estimated

Maximum Day water usage is 173,250 gallons per day.

Fire flows are commonly defined by the local “Fire Protection Authority Having Jurisdiction” or FPAHJ.

When there are no local written standards, Annex H of the Uniform Fire Code indicates residential

areas should have access to a 1,000 gallons per minute (gpm) flow for one hour, or 60,000 gallons of

fire reserve.

The Uniform Fire Code also indicates the smallest fire flow for commercial structures is 1,500 gpm with

two hour duration. The Uniform Fire Code allows this flow to be reduced to 1,000 gpm with a two hour

duration if the buildings are fire sprinkled. The City is a mostly residential community, but also contains

a few commercial buildings, so the commercial fire protection numbers in the Uniform Fire Code are

probably appropriate. Many rural communities also have fairly small diameter distribution lines and

can’t flow a 1,500 gpm fire demand. Instead, many adopt a flow of 1,000 gpm with two hour duration

(120,000 gallons) as their fire flow requirement.


TABLE 2 WATER CONSUMPTION

Month Gallons Per Day

January 42,000

February 42,000

March 42,000

April 69,300

May 96,600

June 96,600

July 96,600

August 96,600

September 69,300

October 42,000

November 42,000

December 42,000

Average 64,750

Water Supply

The City utilizes groundwater as its water supply through two wells. Well No. 1 was drilled in 1956 to a

depth of 120 feet and has a capacity of 30 gpm or 43,200 gpd. The pumps in Well No. 1 were replaced

approximately two years ago. Well No. 2 was drilled in 1992 to a depth of 1,480 feet and has a

capacity of 45 gpm or 64,800 gpd. Both wells produce water with excessive total dissolved solids and

require treatment before distribution to the water system customers. Well No. 2 is presently

inoperable due to a lightning strike in the summer of 2011, but is scheduled for repair in the summer

of 2012. Well No. 3 was constructed but has been abandoned due to very poor quality water. The total

existing well capacity is currently only 43,200 gpd, but should increase to 108,000 gpd when Well No. 2

is repaired and back on line.

In discussions with City officials, possible solutions to water quality and quantity issues include the

drilling of additional well(s) for increased capacity in an aquifer with better water quality. Based on

existing well capacities of 30 gpm and 45 gpm and the Ten States Standards requirement to test pump

at 1.5 times the production rate, two new wells would be needed to meet the projected Maximum Day

demands. Alternative water supplies include the North Prairie Rural Water System, located four miles

to the east, or the Fort Berthold Rural Water System, located approximately ten miles west of the City.

Ten States Standards also require a water system to be able to meet its Maximum Day demand with its

largest well out of production. The maximum day demand is estimated at 173,250 gpd. Water


production is only 43,200 gpd with Well No.2 assumed to be out of production. The City’s water system

needs to be able to produce an additional 130,050 gpd (90 gpm) to be in compliance with Ten States

Standards. Since Well No. 1 produces about 30 gpm and Well No. 2 produces an estimated 45 gpm, it is

assumed the City will need two additional wells.

A groundwater study was completed for the City in 1986 as State Water Commission (SWC) Project

#1821. The study drilled 21 test wells with a total of 2,430 feet. Six observation wells were completed

and five sets of water samples were taken. The study recommends additional wells be drilled as need

in an area about two miles north of the City. The water in this area contain about half the total

dissolved solids as the aquifer currently serving the City.

Water Treatment

The water treatment facility is a traditional filtration treatment system. The facility is approximately 20

years old and is in relatively poor condition. The treatment system utilizes potassium permanganate

oxidize iron and manganese and two greensand filters to remove the insoluble suspended

contaminants. Potassium permanganate is also use to aid in the oxidation of hydrogen sulfide (rotten

egg smell) from the well water. The design flow rate through the filters is 75 gpm.

The new wells are estimated to produce an additional 90 gpm and will likely require two additional

filters although more analysis should be completed in the future to ascertain whether filtration could

be eliminated for the new water supplies. In addition, the current filters are nearing the end of their

useful life and should be replaced. Four new filters should be installed for the City’s water system.

Water Distribution and Storage

In 1988, the original cast iron water distribution pipelines

were replaced with PVC pipe of the same diameter. The

existing water tower was constructed in 1955 and has been

on a regular maintenance schedule. The distribution system

has not experienced water breaks since 1988 and the water

tower was rated in “good condition” by City officials. The

storage capacity of the water tower is 50,000 gallons (per

original plans).

With anticipated water storage requirements of 120,000

gallons for fire flows and 64,750 gallons for domestic use

needed, the total storage required to serve the additional

developments is approximately 184,750 gallons. Assuming

the current water tank is in good operating condition and will continue to be useable, the new storage


tank should be at least 134,750 gallons. Since water tank sizes are typically rounded to the nearest

nominal tank size, the new elevated water tank should be at least 150,000 gallons.

The City presently is not metering individual services or well production and potential water loss issues

cannot be identified because of the lack of metering. The water rates currently in place are a flat fee of

$17.00 per month. The City carries no long term debt on the water system infrastructure.

Water Supply Improvement Alternatives

Two alternatives were considered to address the deficiencies in the water supply system. The first

alternative includes continued use of the existing groundwater (well) source with the addition of two

water wells and 150,000 gallon elevated water tank. Table 3 includes the Opinion of Probable Cost for

two additional water wells and a new elevated water tank. The second alternative examined was to

connect the City to the North Prairie Rural Water System located approximately four miles from the

City assuming this system has adequate water supply to meet the City’s water demands. Additional

investigations will be needed to determine the actual feasibility of this alternative. Table 4 includes the

Opinion of Probably Cost to connect the City to the North Prairie Rural Water System and install a new

elevated water tank.

The second alternative to address the water supply shortage is to connect to the North Prairie Rural

Water System. Pipe diameter is a critical issue when moving water through over 21,000 feet of pipe

and 12-inch PVC will be required to keep head loss to a minimum under the 1,000 gpm fire flow. An

elevated water tank is also required for this alternative.


TABLE 3

OPINION OF PROBABLE COST

PLAZA WATER SYSTEM IMPROVEMENTS

INSTALL TWO NEW WATER WELLS

# DESCRIPTION QTY UNIT UNIT PRICE 1 TOTAL

1 Public Water Well ~ 400' Deep 2 Each $ 20,000.00 $ 40,000

2 6" PVC - Class 160 10,560 Feet $ 25.00 $ 264,000

3 Pumphouse 2 Each $ 20,000.00 $ 40,000

4 150,000 gallon elevated water tank 150,000 Gallon $ 3.00 $ 450,000

5 Filter Assemblies 4 Each $ 20,000.00 $ 80,000

6 Disinfection Facility - new wells 1 Each $ 35,000.00 $ 35,000

7 Telemetry - New Wells 1 Each $ 40,000.00 $ 40,000

8 Backup Power Generator 1 Each $ 75,000.00 $ 75,000

9 Landscaping 1 Each $ 2,000.00 $ 2,000

10 Electrical 1 Each $ 25,000.00 $ 25,000

11 Valves, fittings 1 LS $ 7,500.00 $ 7,500

Direct Construction Subtotal $ 1,058,500

Mobilization/Bonding/Insurance 8.0% $ 85,000

Traffic Control Lump Sum

$ 25,000

Contingency 15% $ 159,000

Construction Subtotal (2012 dollars) $ 1,328,000

2014 Construction Cost 2 3.1% $ 1,412,000

Land Acquisition 1 acre @ $ 12,000 $ 12,000

Right-of-Way & Permits

$ 25,000

Engineering 20% $ 266,000

Legal & Administrative 5% $ 66,000

TOTAL $ 1,781,0003

1 Estimated unit costs are based upon estimates from suppliers and recent bid tabs for similar projects throughout region.

2 The ENR 20 year average Construction Cost Index is +3.1% (as of November 2009), so capital costs are projected to an anticipated

construction date in 2014 using an annual 3.1% inflation rate.

3 Estimates are rounded to nearest thousand


TABLE 4


PLAZA WATER SYSTEM IMPROVEMENTS

CONNECTION TO NORTH PRAIRIE WATER SYSTEM


1 12 Inch Class 160 PVC 21,120 Feet $ 40.00 $ 844,800

2 Connection to existing main 2 Each $ 2,500.00 $ 5,000

3 12" Gate Valves 21 Each $ 4,000.00 $ 84,000

4 Control Valve Assembly & Vault 2 Each $ 15,000.00 $ 30,000

5 150,000 gallon elevated water tank 150,000 Gallon $ 3.00 $ 450,000

Direct Construction Subtotal $ 1,414,000



$ 4,000





$ 25,000



TOTAL $ 2,314,000

1 Estimated unit costs are based upon estimates from suppliers and bid tabs for similar projects throughout region.



This cost opinion does not include the purchase cost of the water utilized.

WASTEWATER SYSTEM ASSESSMENT AND IMPROVEMENT RECOMMENDATIONS

Existing System

The wastewater system serving the City of Plaza consists of a collection system that conveys

wastewater to a lift station. The lift station pumps raw wastewater to a 2.7 acre facultative treatment

lagoon located north of the City. The lagoon is permitted to discharge, although discharges have not

been necessary except in 2011 as a result of infiltration and inflow (I/I) caused by the heavy winter

snows and higher than normal precipitation.


System Loading

Based on the proposed new project development information submitted to the City, the future design

population is estimated at 420 people. The average domestic wastewater flows generated by the

population in the City in the near future are estimated at 52,000 gpd (36 gpm) based on 140 gpcd for

the current population on the existing collection system (higher I/I) and 100 gpdc for expansions. The

future peak hour factor is assumed at 5.0, which is typical for small communities in this region. The

peak flow is estimated to be 180 gpm.

Collection System Existing Conditions and Deficiencies

The existing sewer system was installed in 1956, and is constructed of vitrified clay pipe. City officials

indicated they employ a regular jetting program and clean a portion of the system every year. City

officials noted that, in general, the collection system has not incurred any known major problems or

system failures. In 2011, there was an issue with I/I into the system, which overloaded the lift station.

This issue has since ceased, and the original cause of the I/I has not been determined. One other issue

identified by City officials is tree roots occasionally obstructing pipelines.

The existing lift station is a duplex USEMCO in-ground unit installed in 1987. The lift station is

functional but is at the end of its useful life, where operation and maintenance costs have increased

and reliability has decreased. The capacity of the lift station was estimated by City officials as 300 gpm.

City officials also stated that they felt the discharge pipe (four-inch diameter) may be limiting the lift

station’s capacity. The velocity in a four-inch forcemain with a flow of 300 gpm is approximately 7.7

feet per second (fps). Minimum required velocities are two feet per second to prevent deposition of

solids and to maintain a “scouring” condition in the pipe.

If a six-inch forcemain was installed, the velocity would drop to 3.2 fps which still meets the minimum

required velocity but would be much more energy efficient. Additionally, a six-inch forecemain is

recommended as the minimum size to reduce potential clogging. The lift station replacement was

given second priority by City officials.

Collection System Recommended Improvements

The existing lift station features a high flow rate under most normal operating conditions and is

approaching the end of its useful service life, making it a likely candidate for replacement or major

rehabilitation. The calculated peak hour wastewater flow rate to serve the future population is 180

gpm. I/I needs to be further assessed to determine a final design flow rate. The existing lift station

should be replaced with a new submersible 180 gpm lift station, which would operate more efficiently,

and have lower associated operating costs. The cost opinion for the lift station replacement is included

in Table 5.


TABLE 5


PLAZA WASTEWATER SYSTEM IMPROVEMENTS

LIFT STATION REPLACEMENT


1 Lift Station 1 EA $ 105,000.00 $ 105,000

2 Valves 4 EA $ 4,000.00 $ 16,000

3 Piping 1 EA $ 10,000.00 $ 10,000

4 Emergency Generator/Electrical/I&C 1 EA $ 100,000.00 $ 100,000

Direct Construction Subtotal $ 231,000

Mobilization 8% $ 18,500

Traffic Control 1%

$ 2,500


Construction Subtotal (2012 dollars) $ 287,000

2014 Construction Cost 2 3.1% $ 296,000

Geotechnical Investigation

$ 10,000



TOTAL $ 380,000

1 Estimated unit costs are based upon estimates from suppliers and bid tabs for similar projects throughout the region.

2 The ENR 20 year average Construction Cost Index is +3.1%, so capital costs are projected to an anticipated construction date in 2012

using an annual 3.1% inflation rate.

Note: It is assumed that developers will bear the cost of sewer service lines to and within their developments.

Treatment System Existing Conditions and Deficiencies

The City employs a single cell lagoon to treat the wastewater. At first glance, this lagoon appears to

operate as a total retention facility much of the time and only discharges as needed during times of

heavy I/I. The lagoon was constructed in 1955 and solids have not been removed during its operation.

According to the original plans, the pond has a five foot side water depth with three foot of freeboard

from the top of the berm. The bottom two feet of a lagoon is typically reserved for sludge

accumulation and the remaining three feet is considered the operating volume, which is estimated as

2.52 million gallons. The existing lagoon measures 370 feet by 320 feet, with a surface area of 2.7

acres.


City officials stated, to the best of their knowledge, the pond has never used an outlet for release with

the exception of 2011 when effluent drained into the nearby slough/pothole. The current wastewater

flow, based on a population of 250, is estimated to be 35,000 gpd or 12.8 million gallons per year.

According to a USGS Evaporation Study, evaporation in this area occurs at an average rate of

approximately 28 inches per year. A weather gauging station in nearby Minot, North Dakota indicates

the average annual precipitation is 17.2 inches per year. Net evaporation is estimated as 10.8 inches

per year and the estimated evaporation from the lagoon per year is 0.80 million gallons. Evaporation

accounts for about six percent of the estimated annual flow. Evaporation does not account for water

loss. Note that the evaporation occurs predominately in the summer, so the winter 180-day storage

does not benefit from evaporation.

City officials indicate there is no observed overflow from the lagoon most of the time. It is estimated

94 percent of the flow is assumed to percolate into the shallow groundwater aquifer. A review of the

NRCS soils in the area indicates most of the local soils are various loams and will readily percolate. The

original wastewater treatment facility plans do not indicate that a clay or synthetic liner was used to

line the cell and local native soil material was probably used for constructing the embankments. The

lack of a liner allows seepage into the groundwater.

Current North Dakota Department of Health (NDDH) regulations do not allow rapid infiltration basins

as a means of discharging wastewater to groundwater but require treated effluent to be discharged to

a surface stream or river. It appears the wastewater system serving the City discharges most of its

effluent to groundwater. Currently, the City holds a discharge permit allowing discharge from the

lagoons to Class III waters. This permit expires September 30, 2014. In order to reduce discharge to

groundwater, the existing lagoon would likely have to be lined and additional lagoon treatment and

storage would have to be constructed.

The future design criteria are based on a population of 420 with assumed flows as previously stated

and biological oxygen demand of 0.18 pounds of BOD per population equivalent (PE). The sizing of the

future treatment lagoon system is presented in Table 6.

Ten States Standards requires the treatment area for small systems be divided into two cells or three

cells. The City’s system can be considered a small system and a second cell is required to provide an

additional 6.84 million gallons of storage (9.36 million gallons total). A six foot side water depth cell is

assumed, which also provides approximately 5.3 acres of surface area.

The current wastewater rates are $7.00 per month and there is no long-term debt associated with the

wastewater system.


Treatment System Recommended Improvements

The existing lagoon cell needs to be lined and a secondary lagoon cell needs to be added to provide

additional storage to meet the design criteria. The proposed treatment system improvements were

sized based on the primary lagoon BOD loading rate, the total system BOD loading rate, and the 180-

day storage volume. All three evaluation criteria should be met for successful wastewater treatment,

so the most restrictive of these criteria controls the evaluation. Additionally, disinfection is required,

which happens naturally with adequate retention time due to pathogen die-off. The 180-day storage

requirement controls the design sizing for the expansion.

TABLE 6 WASTEWATER TREATMENT REQUIREMENTS

EXISTING SYSTEM

EXISTING CAPACITY AT FUTURE FLOW/LOAD

DESIGN CRITERIA

REQUIRED IMPROVEMENTS

Hydraulic Retention 48 days storage at 52,000 gpd

180 days storage capacity (minimum)

Additional 132 days storage capacity (additional cell required, hydraulic controls design)

Primary Cell BOD Loading

28 ppd BOD per acre at 75.6 ppd

30 ppd BOD per acre (maximum)


Overall BOD Loading


20 ppd BOD per acre (maximum)

9.5 ppd BOD per acre at 75.6 ppd

The improvements required to address the treatment system deficiencies include:

Remove sludge from existing system

Install synthetic liner in the existing cell

Install secondary lagoon cell

Install outlet structure, manhole, and piping

The cost opinions for the improvements are shown in Table 7.


TABLE 7 OPINION OF PROBABLE COST

PLAZA WASTEWATER SYSTEM IMPROVEMENTS

LAGOON SYSTEM UPGRADE TO 52,000 GPD

# DESCRIPTION QTY UNITS UNIT PRICE 1 TOTAL

1 Embankment 21,500 CY $ 4.00 $ 86,000

2 Sludge Removal 740,000 gallons $ 0.20 $ 148,000

3 Synthetic Liner 345,000 SF $ 0.60 $ 207,000

4 Liner Cover Material 13,000 CY $ 2.00 $ 26,000

5 Topsoil stripping 6 - 12" deep 265,019 SF $ 0.20 $ 53,004

6 Erosion Control 1 LS $ 25,000.00 $ 25,000

7 Rip rap - ten feet wide - 1/2 perimeter 2,100 SY $ 60.00 $ 126,000

8 Excavation 23,310 CY $ 4.00 $ 93,240

9 Geotextile Under Rip Rap 2,100 SY $ 1.50 $ 3,150

10 Splash Pads 3 EA $ 500.00 $ 1,500

11 Flow Distribution Manhole 1 EA $ 10,000.00 $ 10,000

12 Outlet Structure 1 EA $ 30,000.00 $ 30,000

13 Lagoon Staff Gauges 3 EA $ 2,000.00 $ 6,000

14 12 inch PVC - lagoon piping 1,200 LF $ 40.00 $ 48,000

15 12 inch Gate Valves 5 EA $ 4,000.00 $ 20,000

16 Erosion Control 1 EA $ 15,000.00 $ 15,000

17 Manholes - lagoon piping 6 EA $ 3,500.00 $ 21,000

18 Outfall Structure 1 EA $ 10,000.00 $ 10,000




$ 25,000 Contingency 15% $ 293,000



Land Acquisition 10acres @ $12,000 $ 120,000


$ 25,000

Geotechnical Investigation

$ 15,000

Engineering 20% $ 486,000 Legal & Administrative 5% $ 121,000

TOTAL $ 2,258,0003

1 Estimated unit costs are based on estimates from suppliers and recent bid tabs for similar projects throughout the region.



3 Estimates are rounded to nearest thousand


STORMWATER SYSTEM ASSESSMENT

The City of Plaza does not own or utilize stormwater system infrastructure. There are no immediate

stormwater system improvements required.

STREET ASSESSMENT AND RECOMMENDED IMPROVEMENTS

The City of Plaza's street system is a mixture of both gravel and paved streets. The paved streets were

installed in 1962. There is curb and gutter and sidewalks in the Business District of the City. City

officials noted that the Business District has had a number of overlays over since 1962. Due to the

numerous overlays, the pavement has become increasingly thick and surface drainage has been

adversely affected in this area. There is typically no curb and gutter in the residential areas of the City.

The City repairs pot holes on a fairly frequent basis but streets still exhibit signs of cracking in heavy

traffic areas and have sustained settling/dips in some places. In general, the streets are in fair

condition however increased truck traffic in the area around the central park and in the business

district will continue to affect the condition of the streets in and around the City. The City currently

carries no debt on the street system.

Street System Recommended Improvements

In late 2011, the City applied for Energy Development Infrastructure and Impact Fund support for a

proposed mill and overlay of Covell Street, 3rd and 4th Avenues, Main Street, and West Plaza Street to

address energy development impacted streets. The updated opinion of probable cost is presented

Table 8.


TABLE 8


PLAZA STREET IMPROVEMENTS


1 Milling Asphalt Surface 14,972 SY $ 6.76 $ 101,211

2 1.5 inch overlay (asphalt) 14,972 SY $ 12.00 $ 179,664

3 Full Depth Asphalt Repair 500 SY $ 53.00 $ 26,500

4 Adjust Gate Valve Box 10 EA $ 850.00 $ 8,500

5 Adjust Manhole Casting 5 EA $ 1,200.00 $ 6,000


Mobilization 8.0% $ 26,000


$ 40,000


Construction Subtotal (2012 dollars) $ 436,000

2014 Construction Cost 2 3.1% $ 463,000



TOTAL $ 572,0003

1 Estimated unit costs are based upon estimates from suppliers and bid tabs for similar projects throughout region.


construction date in 2014 using an annual 3.1% inflation rate. 3 Estimates are rounded to nearest thousand


CONCLUSION

A solution to the City of Plaza’s limited water resources is imperative to the future growth of the City to

support a projected population of 420 people and beyond. City officials classified water system

improvements as the top priority for the City. Additionally, if water supplies were available, the City

would like to develop a water depot for industrial sales that would be constructed in the southeast

section of the City.

The second priority of City officials is the replacement of the existing lift station. Further wastewater

system assessments may be needed to fully evaluate the collection system and treatment systems.

Currently, it is known that expansion to the west of the City is prohibited by the existing sewer depth

that inhibits gravity flow to the existing lift station. Expansion to the west would require the installation

of additional sewer lift stations. The wastewater lagoon is also most likely undersized for the projected

population growth and is at risk of NDDH regulatory violations.

Street conditions are fair, but will most likely be affected negatively by the increased truck traffic in

the area due to continued oil well drilling in Mountrail County. Mountrail County is expected to

continue to be a heavily drilled area in the near future due to the high performance of oil wells in this

region.

In conclusion, the City will need to implement between $5 million to $5.5 million in water, wastewater,

and street infrastructure improvements to address current deficiencies and meet pending

development demands from an increased population of approximately 420 people.

The work that provided the basis for this publication was supported by funding under an award with the U.S. Department of Housing and

Urban Development. The substance and findings of the work are dedicated to the public. The author and publisher are solely responsible

for the accuracy of the statements and interpretations contained in this publication. Such interpretations do not necessarily reflect the

views of the Government.

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