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Published by info, 2020-10-01 13:37:11

2018 Water Master Plan

2018 Water Master Plan

WATER SYSTEM
MASTER PLAN

205 Executive Court
Little Rock, AR 72205

501-664-1552
www.cristengineers.com

June
2018

Crist Job No. 1560

WATER SYSTEM MASTER PLAN
City of Hot Springs, Arkansas
June 2018

Table of Contents

I. Introduction............................................................................................................... 1
II. Water Demand.......................................................................................................... 4
III. Existing Water Sources ............................................................................................ 6

A. Ouachita River / Upper Lake Hamilton............................................................... 6
B. Lake Ricks ......................................................................................................... 7
IV. Lakeside Water Treatment Plant .............................................................................. 8
A. General .............................................................................................................. 8
B. Rapid Mix Basin ................................................................................................. 9
C. Flocculation Basin............................................................................................ 10
D. Sedimentation Basins ...................................................................................... 11
E. Filters ............................................................................................................... 13
F. Clearwell .......................................................................................................... 14
G. Lakeside WTP Assessment Summary............................................................. 15
H. Summary of Lakeside WTP Recommended Improvements ............................ 16
I. Lakeside WTP Treatment Costs ...................................................................... 17
V. Ouachita Water Treatment Plant ............................................................................ 18
A. General ............................................................................................................ 18
B. Rapid Mix Basin ............................................................................................... 19
C. Flocculation / Sedimentation Basins ................................................................ 20
D. Filters ............................................................................................................... 20
E. OWTP Clearwells............................................................................................. 21
F. High Service Pumps ........................................................................................ 22
G. Chemical Feed................................................................................................. 22

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. i

H. Instrumentation and Controls........................................................................... 22
I. Sludge Lagoons and Sludge Drying Beds ....................................................... 22
J. Recommended Improvements......................................................................... 23
K. Ouachita WTP Treatment Costs ..................................................................... 23
VI. Distribution System................................................................................................. 24
A. Distribution and Storage System Zones........................................................... 24
B. Inventory of Existing Water Pipes .................................................................... 34
C. Pumping Facilities............................................................................................ 36
D. System Storage ............................................................................................... 42
E. Pressure Reducing Valves............................................................................... 53
F. Water Meters ................................................................................................... 55
G. Fire Hydrants ................................................................................................... 55
VII. Hydraulic Analysis .................................................................................................. 57
A. General ............................................................................................................ 57
B. Demand Allocation........................................................................................... 58
C. Design Criteria ................................................................................................. 62
D. Existing System Simulation.............................................................................. 63
E. Fire Flow Scenarios ......................................................................................... 68
F. Water Age Simulation ...................................................................................... 70
G. Future Demand Scenarios ............................................................................... 71
VIII.Recommended Improvements................................................................................ 72
A. Storage Tank Projects ..................................................................................... 72
B. Water Line Improvement Projects.................................................................... 74
C. Pump Station Improvements............................................................................ 78
D. Ouachita Pressure Zone Expansion ................................................................ 79
E. Supply and Treatment Improvements.............................................................. 83
F. Distribution System Improvements .................................................................. 84
IX. Capital Improvement Plan ...................................................................................... 89
A. Cost Estimating Criteria ................................................................................... 89
B. Capital Improvement Plan................................................................................ 90

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. ii

Table of Figures

Figure 1 - Service Area Map................................................................................. 3
Figure 2 - Daily Water Produced at Both Water Treatment Plants, 2012-2017 .... 4
Figure 3 - Ouachita Water Treatment Plant and Raw Water Intake...................... 6
Figure 4 - Rapid Mix Basin ................................................................................... 9
Figure 5 - Flocculation Basin .............................................................................. 10
Figure 6 - Serpentine Weir ................................................................................. 12
Figure 7 - LWTP Clearwells................................................................................ 14
Figure 8 - Lakeside Water Treatment Plant........................................................ 15
Figure 9 - Rendering of OWTP ........................................................................... 18
Figure 10 - Rapid Mix Basin ............................................................................... 19
Figure 11 - Existing Pressure Zones Map .......................................................... 25
Figure 12 - Music Mountain Ground Storage Tank............................................. 26
Figure 13 - Highway 70 Elevated Storage Tank ................................................. 26
Figure 14 - Lakeside WTP High Service Pumps................................................. 28
Figure 15 - Holly Street Ground Storage Tank ................................................... 28
Figure 16 - Twins Ground Storage Tanks........................................................... 29
Figure 17 - Royal Pump Station.......................................................................... 30
Figure 18 - Industrial Park Elevated Storage Tank ............................................. 30
Figure 19 - Vicinity Map - Water Storage Tanks ................................................. 32
Figure 20 - Water Distribution Process Flow Diagram........................................ 33
Figure 21 - Cast Iron Pipes................................................................................. 34
Figure 22 - Ouachita WTP - High Service Pump Station .................................... 36
Figure 23 - Existing Pine Street Pump Station.................................................... 41
Figure 24 - 250,000 Gallon Elevated Industrial Park Storage Tank.................... 42
Figure 25 - Useable Storage Diagram ................................................................ 44
Figure 26 - Typical Maximum Day Demand Curve ............................................. 45
Figure 27 - Flow Control Valve with Pressure Reducing Feature ....................... 53
Figure 28 - Modified Maximum Day Demand Allocation..................................... 59
Figure 29 - Residential, Sprinkler, Commercial and Industrial Meters Mapped .. 60
Figure 30 - Residential Demand Pattern ............................................................ 61
Figure 31 - Commercial Demand Pattern ........................................................... 62
Figure 32 - 2012 Maximum Day Demand Curve = 23.00 MGD .......................... 64
Figure 33 - Existing System - High Velocity Lines .............................................. 66
Figure 34 - City High Pressure Areas ................................................................. 67
Figure 35 - Low Fire Flow Locations................................................................... 69
Figure 36 - Tank Mixing System ......................................................................... 72

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. iii

Figure 37 - Rendering 3 MG Tank ...................................................................... 73
Figure 38 - Proposed 12" Water Main Television Hill Rd to Country Club Dr ..... 75
Figure 39 - Proposed 24" Water Main Carpenter Dam Rd to Malvern Ave......... 76
Figure 40 - Proposed 12" Water Line Carpenter Dam Road .............................. 77
Figure 41 - Proposed 20" Transmission Main to Pine Street Pump Station........ 78
Figure 42 - Premanufactured Pump Station - Floor Plan.................................... 78
Figure 43 - Proposed Ouachita Pressure Zone Expansion ................................ 79
Figure 44 - Ouachita System Proposed 6" and 8" Water Lines .......................... 81
Figure 45 - Pressure Zone Conversion............................................................... 82

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. iv

Index of Tables

Table 1 - Water Demand Projections.................................................................... 5
Table 2 - LWTP Sedimentation Basins............................................................... 11
Table 3 - LWTP Assessment Summary.............................................................. 15
Table 4 - LWTP Treatment Cost......................................................................... 17
Table 5 - Filters 1-9 ............................................................................................ 21
Table 6 - OWTP Assessment Summary............................................................. 23
Table 7 - Existing Pressure Zones...................................................................... 24
Table 8 - Distribution Pipe Inventory................................................................... 35
Table 9 - Overview of Existing Pump Stations.................................................... 37
Table 10 - Pump Station Capacity - Current Maximum Day Demand................. 37
Table 11 - Pump Station Capacity - 2030 Maximum Day Demand..................... 39
Table 12 – Pumping Station Capacity - 2040 Maximum Day Demand ............... 40
Table 13 - Summary of Existing Water Storage Tanks....................................... 43
Table 14 - Equalization Storage Requirements by Pressure Zone ..................... 46
Table 15 - Fire Protection Storage Requirements by Pressure Zone ................. 47
Table 16 - Emergency Storage Requirements by Pressure Zone ...................... 48
Table 17 - Total Storage Requirements by Pressure Zone ................................ 49
Table 18 - Storage Eval. for Pressure Zones under Existing Max Day Demand50
Table 19 - Storage Eval. for Pressure Zones under 2030 Max Day Demand..... 51
Table 20 - Storage Eval. for Pressure Zones under 2040 Max Day Demand..... 52
Table 21 - Summary of Active PRVs .................................................................. 54
Table 22 - Modified Maximum Day Demand ...................................................... 59
Table 23. Recommended Supply and Treatment Improvements....................... 83
Table 24 - Near-Term Distribution System Improvements.................................. 84
Table 25 – Mid-Term Distribution System Improvements................................... 86
Table 26 – Long-Term Distribution System Improvements................................. 87

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. v

Appendices

Appendix A 2016 Arkansas Department of Health – Sanitary Survey
Appendix B 2017 Arkansas Department of Health – CT Analysis Report
Appendix C 2018 Arkansas Department of Health – WTP Capacity

Exhibits Water Distribution System Map
Water Distribution System Improvements Map
Exhibit I
Exhibit II

Attachments

Capital Improvement Plan – Separate Bound Document
2017 Water Supply Study – Separate Bound Document

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. vi

WATER SYSTEM MASTER PLAN
City of Hot Springs, Arkansas
June 2018

I. Introduction

Hot Springs is the 11th largest city in Arkansas and covers more than 22,000 acres
(35 square miles). The City has a water service area of approximately 92,800 acres
(145 square miles). The City’s Utilities Department provides
potable drinking water to two wholesale water systems --
Mountain Pine and Riviera Utilities (Diamondhead). In
addition, the North Garland County Rural Water District has
an emergency connection. The water service area also
includes the Royal Water District, which includes a rural,
unincorporated area west of the City.

The Utilities Department is responsible for sourcing, treating, monitoring, storing,
and delivering safe, clean water to the community. The existing water supply
system consists of two raw water intake structures, two water treatment plants,
approximately 874 miles of potable water transmission lines, five booster pump
stations, and 13 water storage facilities.

In 2017, a Water Supply Study was prepared by Crist Engineers addressing the
service area population, projected water demands through the year 2060, and
alternate water sources available for securing a future water supply for the City.
The Study, referenced throughout this report, also evaluated water quality from
each source and included estimated construction cost that would be associated
with each supply option.

In 2017, the City made the decision to pursue the Lake Ouachita Water Supply
option as outlined in the Water Supply Study. The development of this new water
supply for the City of Hot Springs includes the following new facilities:

• A new water intake structure on Lake Ouachita
• A new 15 million-gallon-per day (MGD) water treatment plant on the south

side of the water system in the Amity Road area.
• A new raw water line from the intake structure to the new treatment plant.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 1

• New finished water lines from the new water plant to the existing distribution
system.

The City has recognized a need for a long-term plan that would ensure
sufficient supply, adequate capacity, and exceptional quality of potable water
for its current and future customers. This Water System Master Plan includes
the following scope of work:

• Service area population and water demand projections
o Taken from the Water Supply Study

• Evaluate water quality and source
o Taken from the Water Supply Study

• Evaluate existing system and facilities
• Improvements needed to meet future demand projections
• Recommended immediate, near, and long-term water system

improvements over the planning period
• Recommended Capital Improvement Plan (CIP), including cost estimates
• Water age assessment

In accordance with direction from the City, the Water System Master Plan work
focuses on availability, redundancy, reliability, sustainability, and quality of service
of the water system.

The City utilizes a hydraulic model of its water distribution system that is
maintained and operated by Crist Engineers, Inc. The water system hydraulic
model uses InfoWater software in an ArcGIS platform. Data was obtained from the
City’s GIS department, record drawings, City employees, City water usage data,
and distribution system site surveys to update and develop the hydraulic model.
Results from model simulations were analyzed and greatly assisted with creating
and prioritizing the capital improvement projects listed in this report. The projects
listed in the long-term capitol improvement plan are intended to be constructed as
funds become available.

The hydraulic analysis used for the evaluation of the water system in this plan is
predicated on the fact that the new water treatment plant near Amity Road will be
placed in service during the planning period.

Figure 1 shows the current service area map for the City of Hot Springs.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 2

Figure 1 - Service Area Map 3
City of Hot Springs – Water System Master Plan | Crist Engineers, Inc.

II. Water Demand

Historical water production data from the Ouachita Water Treatment Plant (OWTP)
and the Lakeside Water Treatment Plant (LWTP), presented in Figure 2 below,
was obtained from monthly Surface Water Operation and Chemical Reports
submitted by the City to the Arkansas Department of Health (ADH). These records
were provided by the City.

The daily finished water produced at both water treatment plants from 2012
through 2017 is shown in Figure 2. The historical maximum daily combined
production from both plants was 23.08 million gallons per day (MGD) on July 6,
2012. The average daily volume of finished water produced during 2012-2017 is
approximately 15.2 MGD. The wholesale customers of Diamondhead and
Mountain Pine consumed 0.148 and 0.074 MGD, respectively, during average day
demand according to the 2016 ADH Sanitary Survey. The ADH Sanitary Survey
(included in Appendix B) lists the maximum day demand for the wholesale water
users as 0.267 MGD for Diamondhead and 0.088 MGD for Mountain Pine. The
water supply agreement for Mountain Pine specifies the City provide up to 121,000
gallons per day (GPD) on average plus fire flow.

PRODUCTION (MGD) DAILY FINISHED WATER PRODUCTION Lakeside
2012-2017 Ouachita

25 Max Day (7/6/2012) = 23,081,000 GAL

20

15

10 Average Day = 15.25 MGD

5

0

1/1/2012
4/1/2012
7/1/2012
10/1/2012
1/1/2013
4/1/2013
7/1/2013
10/1/2013
1/1/2014
4/1/2014
7/1/2014
10/1/2014
1/1/2015
4/1/2015
7/1/2015
10/1/2015
1/1/2016
4/1/2016
7/1/2016
10/1/2016
1/1/2017
4/1/2017

DAY
Figure 2 - Daily Water Produced at Both Water Treatment Plants, 2012-2017

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 4

As discussed in the Water Supply Study, from 1976 to present, the maximum day
demand to average day demand (MDD/ADD) ratio, or peaking factor (PF), for the
City’s water system is 1.40. This historical average PF differs from the historical
maximum PF of 1.65 which occurred in 2001.

The average day demand is approximately 15.25 MGD and the historic maximum
day demand is approximately 23.08 MGD. The projected water demands from the
Water Supply Study are shown below in Table 1.

Table 1 - Water Demand Projections Max. Day
Demand
TABLE 1
WATER DEMAND PROJECTIONS* + 15%

Year Avg. Day Demand Max. Day Demand

Current 15.25 MGD 23.08 MGD

2030 17.41 MGD 24.14 MGD 27.76 MGD

2040 18.38 MGD 25.48 MGD 29.30 MGD

* Data taken from Water Supply Study

In 2017, approximately 34,397 meters were active in the City’s distribution system.
This included approximately 28,980 residential meters, 3,102 commercial meters,
2,299 irrigation meters, 14 industrial meters, and 2 wholesale meters.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 5

III. Existing Water Sources

A. Ouachita River / Upper Lake Hamilton

The City of Hot Springs utilizes surface water from the Ouachita River/upper Lake
Hamilton as its primary source for the water system. The raw water intake structure
for the Ouachita Water Treatment Plant (OWTP), as shown on Figure 3 is located
just downstream of Blakely Mountain Dam and pumps water to the OWTP. The
OWTP raw water intake structure has a pumping capacity of 23 MGD.

Figure 3 - Ouachita Water Treatment Plant and Raw Water Intake

Lake Hamilton is owned and regulated by Entergy, Inc. Entergy has restricted the
withdrawal at the OWTP intake to an average of 20 MGD. Therefore, the rated
production of the plant is restricted to 20 MGD on average. The withdrawal may
occasionally exceed 20 MGD (up to 30 MGD) as long as the 90-day rolling average
does not exceed 20 MGD.

From all indications, this source is secure from both a quality and quantity
perspective.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 6

B. Lake Ricks

Lake Ricks is located just north of the downtown area and provides the Lakeside
Water Treatment Plant (LWTP) with its source water. The raw water is gravity fed
from Lake Ricks to the LWTP. Lake Ricks has become more commonly known as
the Hot Springs Reservoir. From the mid 1940’s until 1967, Lake Ricks and three
other small lakes nearby (Sanderson, Dillion, and Bethel) supplied the entire City.

Although the plant is rated by the ADH as having a capacity of 6 MGD, during a
recent attempt by City the plant was only able to produce 4 MGD when running at
full capacity. The 2004 Master Plan report states that “the firm supply (yield based
on a 2-year drought of record) of the three lakes computed to be zero based on
stream gauging in the proximity of Hot Springs”. Firm yield or safe yield is defined
as the maximum quantity of water that can be guaranteed with some specified
degree of certainty during a specific critical drought period.

Even during moderate periods of dry weather, the water level in Lake Ricks draws
down enough to cause the City to reduce withdrawal rates as a precautionary
measure.

From a reliability aspect, the volume of water available from this water supply
during an extended drought (firm yield) is zero.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 7

IV. Lakeside Water Treatment Plant

A. General

The Lakeside Water Treatment Plant (LWTP) was constructed in about 1947.
Lake Ricks is the current water source for Lakeside. During an extended drought,
the firm yield of Lake Ricks is zero. Depending upon how the City uses Lakeside
in the future, if at all, an alternate water source will need to be considered. In
discussions with water treatment staff there seems to be a consensus that the
maximum sustainable capacity of Lakeside is 4 MGD, without taking into
consideration the firm yield of Lake Ricks being zero.

The water treatment process at the Lakeside Water Treatment Plant consists of
the following steps and unit processes:

• Rapid Mix
• Flocculation
• Sedimentation
• Filtration
• Clearwell Storage
• High Service Pumping

Each of these steps and unit processes will be compared to the desired design
flow for the water treatment plant.

The capacity of the Lakeside WTP is rated at 6.2 MGD in the most recent Sanitary
Survey. This approved rated capacity is calculated by the ADH and does not take
into consideration real-world conditions such as downtime required for normal filter
backwash cycles. Off time for filter backwash cycles causes a decrease in the daily
production rating of the plant and should be included when calculating a WTPs
rated capacity. In addition, the ADH evaluation uses the maximum allowable
filtration rate which differs from the actual filtration rate being used at the plant. In
discussions with water treatment staff, it is a consensus that the maximum
sustainable production rate of the Lakeside WTP is 4 MGD.

The ADH has concurred on this maximum sustainable production rate. See
attached letter from the ADH in the Appendix.

A design flow of 4 MGD was used in evaluating each treatment unit process.

Design Flow = 4 MGD = 2778 GPM = 371.36 CFM = 6.19 CFS

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 8

B. Rapid Mix Basin

Raw water is gravity fed into the rectangular rapid mix basin. The rapid mix basin
characteristics are as follows:

• Volume = 20.5’W x 20.67’L x 12.15’D = 5,148.38CF = 38,510 GAL
• Detention Time = 38,510 GAL / 2,778 GPM = 13.86 MIN.

o Current detention time design criteria is 0.5 minutes

Figure 4 - Rapid Mix Basin

Although no issues have been reported with the rapid mix basins effect on water
treatment, the velocity gradients of the rapid mixers in the basin are not known and
could not be evaluated to Ten States Standards (TSS). The rapid mix basin does
not have a drain.

Recommended Improvements

• Install a drain in the basin for maintenance purposes.
• Replace the rapid mix mechanisms.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 9

C. Flocculation Basin

The concrete flocculation basin allows floc to form prior to reaching the
sedimentation basins for settlement. The flocculation basin characteristics are as
follows:

• Volume = 20.68’W x 81.4’L x 12.15’D = 20,452.7 CF = 152,986 GAL
• Detention Time = 152,986 GAL / 2778 GPM = 55 MIN.

o Current detention time design criteria is 30 minutes.
• Cross Sectional Area = 20.68’W x 12.15’D = 251.26 SF
• Flow Through Velocity (FTV) = 371.36 CFM / 521.26 SF = 1.48 FPM

o Current FTV design criteria is 0.5 – 1.5 FPM

Figure 5 - Flocculation Basin

There is no drain to empty the flocculation basin and no baffling between
flocculation stages. The velocity gradient of the flocculators is unknown. The chain
driven flocculators and drive mechanism are pictured above.

Recommended Improvements

• Install a drain in the basin for maintenance purposes.
• Replace the flocculators and drive mechanisms.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 10

D. Sedimentation Basins

There are two sedimentation basins that are used to settle out particles before the
water filtration stage of the water treatment process. The characteristics of the two
basins are listed in Table 2.

Table 2 - LWTP Sedimentation Basins

Parameter Sedimentation Sedimentation Basins 1 & 2
Basin 1 Basin 2 Combined

Length 100.1 feet 100.1 feet

Width 36.4 feet 36.6 feet
Side Water Depth 12.1 feet 12.1 feet

Cross-Section Area 440.44 SF 442.86 SF 883.3 SF
Surface Area
3,644 SF 3,664 SF 7,307 SF
Volume 342,133 344,013 686,146
L:W Ratio GAL GAL GAL
2.75 2.73

Weir Length 122.4 LF 122.4 LF 244.8 LF

• Combined Volume = 686,146 GAL
• Detention Time = 686,146 GAL / 4,000,000 GPD = 0.17 days = 4.12

hours
o Current detention time design criteria is 4 hours minimum.

• Combined Cross-Sectional Area = 883.3 SF
• Flow Through Velocity (FTV) = 371.12 CFM / 883.3 SF = 0.42 FPM

o Current FTV design criteria is less than 0.5 FPM
• Combined Surface Area = 7,307 SF
• Surface Settling Rate = 4,000,000 GPD / 7,307 SF = 547.4 GPD/SF

o Current Surface Settling Rate design criteria is 800-1200
GPD/SF

• Combined Weir Length = 244.8 LF
• Weir Loading Rate = 4,000,000 GPD / 2,448 LF = 16,340 GPD/LF

o Current weir loading design criteria is less than 20,000
GPD/LF

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 11

A picture of the serpentine weir located
at the end of the sedimentation basins
is shown to the right.

There are no sludge collection
mechanisms in either sedimentation
basin.

Recommended Improvements

• Install a sludge collection
system.

Figure 6 - Serpentine Weir

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 12

E. Filters

There are six gravity filters at the LWTP utilizing sand media for filtration. The filter
characteristics are as follows:

• Six filters each 15’ wide x 23’ long
• Surface area per filter = 15’ x 23’ = 345 SF
• Total filter surface area = 6 x 345 SF = 2070 SF
• Filtration rate = 2778 GPM / 2070 SF = 1.34 GPM/SF

In 2006, the Lakeside WTP was placed into Bin 2 of the EPA Long-Term 2
Enhanced Surface Water Treatment Rule; therefore, more stringent treatment
limits are being applied by the ADH. Enhanced filtration utilizing a multi-media
(sand and anthracite) filter cross-section would typically be used to meet these
enhanced requirements. The ADH has recommended filter replacement in the
most recent Sanitary Survey (located in the Appendix).

Filter notes:

• Sand media only.
• No combined air and water backwash.
• Manual filter control system.
• Media, wash water troughs, and underdrains need replacement.
• Backwash rates to some filters are too low.
• Filter control valves and some piping needs to be replaced.

Recommended Improvements

• Complete filter rehabilitation, including:
o Media replacement with new sand and anthracite.
o Installation of combined air and water backwash.
o Installation of new underdrains and wash water troughs.
o Pipe gallery rehabilitation.
o New filter control system.
o Improvements to the backwash water handling system.
o Replace filter control valves and piping.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 13

F. Clearwell

There are two concrete clearwells located at the LWTP. The clearwells have the
following characteristics:

• Clearwell 1 Volume = 327,622 gallons

• Clearwell 2 Volume = 163,811 gallons

• Baffling factor = 0.4

• Chlorine contact time summary:

o Clearwell 1 chlorine contact time: 19.8 minutes

o Clearwell 2 chlorine contact time: 13.6 minutes

o Filter chlorine contact time: 20.5 minutes

o Total chlorine contact time: 53.9 minutes

• The ADH has made the determination that CT compliance can be

achieved with a minimum water level of 6.5 feet in the clearwells.

Clearwell notes:

• Data taken from the ADH Sanitary Survey.
• Clearwell 2 has an approximate 75 GPM leak.
• Vents need rehabilitation including installation of turn-down piping.
• Exterior concrete is in poor condition and needs rehabilitation.

Figure 7 - LWTP Clearwells 14

Recommended Improvements
• Repair clearwell 2 leaks.
• Repair vents.
• Exterior concrete rehabilitation.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc.

G. Lakeside WTP Assessment Summary

The following table summarizes the assessment of the LWTP comparing its water
treatment unit process to current design criteria at a design flow of 4 MGD.

Table 3 - LWTP Assessment Summary

Unit Process Parameter Current Design Actual
Criteria 13.86 minutes
Rapid Mix Detention Time
0.5 minutes

Flocculation Detention Time 30 minutes 55 minutes
0.5-1.5 feet per min. 1.48 feet per min.
Flow Through
Velocity

Sedimentation Detention Time 4 hours 4.12 hours
< 0.5 feet per min. 0.42 feet per min.
Flow Through
Velocity

Surface Settling Rate 800-1,200 GPD/SF 547.4 GPD/SF

Weir Loading Rate < 20,000 GPD/LF 16,340 GPD/LF

Filters Length: Width Ratio 3-6 2.74
Filtration Rate 2 GPM/SF 1.34 GPM/SF

High Service Pumping Capacity 4 MGD 4 MGD
Pumping

Figure 8 - Lakeside Water Treatment Plant 15
City of Hot Springs – Water System Master Plan | Crist Engineers, Inc.

H. Summary of Lakeside WTP Recommended Improvements

Recent upgrades at Lakeside include a standby generator, raw water inlet control
valve, and a sodium hypochlorite feed system. If Lakeside continues to operate,
a fluoride feed system will need to be added to meet current regulations. The filter
backwash water handling system appears to be adequate except for some minor
improvements. This analysis and discussions with Lakeside staff identified the
following improvements:

• Install a drain in the rapid mix basin for maintenance purposes.
• Replace the rapid mix mechanisms.
• Install a drain in the basin for maintenance purposes.
• Replace the flocculators and drive mechanisms.
• Install a sludge collection system in the sedimentation basin.
• Complete filter rehabilitation, including:

o Media replacement with new sand and anthracite.
o Installation of combined air and water backwash.
o Installation of new underdrains and wash water troughs.
o Pipe gallery rehabilitation.
o New filter control system.
o Improvements to the backwash water handling system.
o Replace filter control valves and piping.
• Repair Clearwell 2 leaks.
• Repair clearwell vents.
• Exterior concrete rehabilitation of both clearwells.
• Switch from lime to liquid feed caustic.
• Replace/repair Lake Ricks intake gate control mechanisms.
• Instrumentation and control improvements to enable the plant to run
more reliably and automatically.
• Installation of a fluoride feed system.
• Raw water line improvements to include a valve on the line to enable
an emergency drawdown of Lake Ricks.
• An evaluation of the firm yield of Lake Ricks.

It is estimated that these improvements combined will cost $7-10 million. Arguably,
all the improvements are needed to extend the life of Lakeside WTP about 25
years.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 16

I. Lakeside WTP Treatment Costs

Operating data from 2014, 2015, 2016, and 2017 indicate the following treatment
cost per 1,000 gallons for Lakeside, along with average daily water produced.

Table 4 - LWTP Treatment Cost

Lakeside WTP Treatment Cost

Year Treatment Cost Average Daily Water
2014 per 1,000 Gallons Produced in MGD

$1.19 1.96

2015 $1.02 3.03
2016 $0.79 2.58

2017 $1.61 3.12

Currently, operation of the LWTP is required to serve portions of downtown and all
of the Belvedere area. The City has a plan to upgrade the Pine Street water booster
station, a distribution system improvement later identified in the pumping facilities
section of this report. When this upgrade is complete, Lakeside will not necessarily
be needed, as it is now. The Pine Street pump station will have the ability to serve
the same portion of the distribution system that is currently being served by the
LWTP. This will increase redundancy and allow the City the flexibility to take
Lakeside out of service as/if needed.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 17

V. Ouachita Water Treatment Plant

A. General

The Ouachita Water Treatment
Plant (OWTP) was originally
constructed in about 1967. The
water treatment process consists of
the following steps and unit
processes:

• Rapid Mix Figure 9 - Rendering of OWTP

• Flocculation

• Sedimentation

• Filtration

• Chemical Feed

• Clearwell Storage

• High Service Pumping

• Instrumentation and Controls

• Backwash Pond

• Standby Generator

Each of these steps and unit processes will be compared to the desired design
flow for the water treatment plant.

The capacity of the Ouachita WTP is rated at 22.33 MGD in the most recent
Sanitary Survey. This approved rated capacity is calculated by the ADH and does
not take into consideration real-world conditions such as downtime required for
normal filter backwash cycles. Off time for filter backwash cycles causes a
decrease in the daily production rating of the plant and should be included when
calculating a WTPs rated capacity. In addition, the ADH evaluation uses the
maximum allowable filtration rate which differs from the actual filtration rate being
used at the plant. In discussions with water treatment staff, it is a consensus that
the maximum sustainable production rate of the OWTP is 21 MGD.

The ADH has concurred on this maximum sustainable production rate. See
attached letter from the ADH in the Appendix.

A design flow of 21 MGD was used in evaluating each treatment unit process.

• Design flow = 21 MGD = 14,583 GPM = 1,950 CFM = 32.5 CFS

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 18

B. Rapid Mix Basin

Raw water is pumped into a rectangular concrete basin containing four sections or
chambers. The first two sections are 9’-0” long x 10’-0” wide x 12’-0” deep. In these
sections, the flow of water is split by three adjustable weir gates. The flow is split
between the seven sedimentation basins. The last two 10’-0” square sections are
almost 17’-0” deep and are where rapid mixing occurs. A chemical mixer located
in the center of these two sections provides rapid agitation to mix the incoming raw
water with chemicals that are being fed prior to flocculation and sedimentation. A
drawing of the rapid mix basin is shown below.

Chemical Mixer

RAW WATER
(FROM INTAKE)

RAW WATER
(TO SED BASINS)

Figure 10 - Rapid Mix Basin

Rapid mix effluent flow control was added as a part of the 2016 improvement
project.

The 25,000-gallon rapid mix basin has a more than adequate hydraulic capacity
for current and future plant design flows. A detention time of 1 minute and 44
seconds is achieved at the plant design flow.

The rapid mix basin has an approved capacity of 22.33 MGD by the ADH as listed
in the most recent Sanitary Survey.

Recommended Improvements

• No recommended improvements.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 19

C. Flocculation / Sedimentation Basins

The OWTP has seven rectangular concrete basins where particles are flocculated
and settled out of the incoming raw water. The flocculation basin characteristics
are as follows:

Basins #1 through #5 have a combined hydraulic capacity of 17.55 MGD per the
ADH. Basins #1 and #2 were constructed in 1967 and basins #3 and #4 were
added in 1973. Basin #5 was constructed in 1987 and was the first sedimentation
basin to be equipped with tube settlers. Tube settlers were added to basins #1
through #4 during the 2010 treatment plant expansion.

The larger basins #6 and #7 have a combined hydraulic capacity of 8.0 MGD and
were added during a plant expansion in 1999. In 2016, the capacity of the two
basins was doubled with the installation of stainless steel plate settlers.

The Sanitary Survey located in the Appendix provides the dimensions and design
criteria for the seven sedimentation basins.

Recommended Improvements

• OWTP personnel have reported clogging problems with the existing
sludge collection system in sedimentation basins 1-5. As a
maintenance and operation enhancement project, it is recommended
to replace the existing sludge collection mechanisms with a more
clog-resistant mechanism.

• The troughs in basins 1-5 have reached the end of their useful life
and it is recommended that they be replaced.

D. Filters

The water treatment plant has nine filters in service. The filters are located
downstream of the sedimentation basins. As part of the plant improvement project
in 2017, air backwash will be added to filters 1-6; new filter underdrains will be
installed, along with new troughs, and new media. A media retaining cap will be
installed on the underdrains on Filters 7-9 and the media will be replaced. The
rating capacity of the filters after the improvements are implemented will not
increase. Table 5 shows details of each filter prior to the improvements mentioned
above.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 20

Table 5 - Filters 1-9 Filters 1-6 Filters 7-9
6 3
Parameter
Quantity 12.9 MGD 9.4 MGD
17’ W x 22’ L 17’ W x 31-1/2’ L
Approved Total Capacity 374 square feet 535.5 square feet
Dimensions 4.0 GPM / SF
Area Sand, Anthracite 4.0 GPM / SF
Filtration Rate Sand, Anthracite
Media

Filters 7 – 9 were constructed in 1999.

A new filter enclosure building is scheduled to be constructed along with the filter
rehabilitation. Enclosing the filters will allow for more consistent water treatment.
By removing sunlight there will be less algae growth and therefore less of a need
to pre-chlorinate resulting in a potential reduction in TTHMs.

Recommended Improvements

• There are no recommended improvements to the existing filters
beyond the current project.

E. OWTP Clearwells

Clearwell #1 along with the original high service pump building has been
abandoned since the construction of clearwell #2 in 1993. Clearwell #2 is still in
service but is planned to be bypassed and converted into a sodium hypochlorite
building soon as a part of the filter rehabilitation project. The existing clearwell #3
is currently in use and was constructed in 1999 as part of a plant expansion project.
This 2.5 million-gallon clearwell has a diameter of 156’-0” and is 19’0” deep, but
because the overflow elevation of clearwell #2 is lower than that of #3, the full
depth cannot be utilized until Clearwell #2 is abandoned. Clearwell #3 has a
baffling factor of 0.65 as listed and approved by the Arkansas Department of
Health.

The high service pumps are mounted on top of clearwell #3. A metal frame and
roof were constructed in 2013 over the high service pumps and piping.

Recommended Improvements

• There are no recommended improvements.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 21

F. High Service Pumps

The high service pumps are addressed in the pumping facilities section of this
report.

G. Chemical Feed

The chemicals that are fed include aluminum chlorohydrate (ACH), sodium
permanganate, polymer, fluorosilicic acid, chlorine, zinc orthophosphate, and
caustic.

Recommended Improvements

• The City’s new 15 MGD WTP is being planned to include chlorine dioxide
feed in the raw water for trihalomethane reduction and numerous other
reasons. Chlorine dioxide addition is needed at the OWTP for the same
reasons. The existing chemical feed building is not large enough to
accommodate the chlorine dioxide feed system, so a new building adjacent
to the existing chemical feed building is planned. The proposed chlorine
dioxide feed system is a three-chemical system identical to the one proposed
for the new 15 MGD WTP. Installing the chlorine dioxide feed system will
enhance the OWTP’s ability to provide treated water that can meet the
disinfection by-products standards in the water distribution system.

H. Instrumentation and Controls

Water treatment plant personnel indicate that the instrumentation and controls are
sufficient. Instrumentation and control improvements are included separately with
other recommended improvements.

I. Sludge Lagoons and Sludge Drying Beds

Sludge from the clarifiers and filter backwash is collected in one of the four sludge
ponds located south of the water treatment plant. Sludge from the sludge ponds is
periodically removed and land applied through a land application permit from
ADEQ. A discharge permit also through ADEQ, allows water to be discharged from
the sludge ponds to a nearby stream.

Recommended Improvements

• It is recommended to evaluate the option of mechanically dewatering
backwash waste and sedimentation basin sludge using sludge-dewatering
equipment and sending the concentrate to the existing sludge holding ponds
along with the filter-to-waste water. Solids from the sludge dewatering facility
would be conveyed to a dumpster to be transported to a landfill for disposal.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 22

J. Recommended Improvements

As discussed in the Water Supply Study, one possibility for increasing the capacity
of the OWTP is expanding the existing treatment plant at this location. This option
is not recommended due to several physical and economical restraints. Primarily,
the existing water transmission mains are currently nearing maximum capacity.
New transmission mains would have to be constructed to coincide with a plant
expansion. The other restraint is related to the City’s current agreement with
Entergy that limits the amount of water that can be withdrawn from Lake Hamilton.
Per the Agreement, the 90-day rolling average cannot exceed 20 MGD. Therefore,
the rated production of the plant is restricted to 20 MGD on average until another
water source is secured by the City.

K. Ouachita WTP Treatment Costs

Operating data from 2015, 2016, and 2017 listed in Table 6 indicate the following
treatment cost per 1,000 gallons for the Ouachita WTP, along with average daily
water produced.

Table 6 - OWTP Assessment Summary

OUACHITA WTP TREATMENT COST

Year Treatment Cost Average Daily Water
2015 per 1,000 Gallons Produced in MGD

12.89

2016 $2.53 12.60

2017 $2.27 11.15

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 23

VI. Distribution System

A. Distribution and Storage System Zones

Distribution and storage system zones refer to pressure zones within a water
distribution system. T he City’s water system includes seven pressure zone
systems as summarized in Table 7 below. Separate pressure zones are
g e n e ra l l y utilized to equalize water pressure across an entire water distribution
system in accordance with ground elevation. In a perfect scenario there is a closed
boundary separating each Zone.

Table 7 - Existing Pressure Zones

TABLE 7
EXISTING PRESSURE ZONES

Pressure Zone Reservoir Existing Customer Range of Static
Overflow Service Elevations Service Pressures
Elevations
(ft.) (psi)
(ft.)

Ouachita 710 305 – 620 36 – 173

Holly St / 876 580 – 795 35 – 128
Lakeside

Twins 869 335 – 778 39 – 231

Crystal Springs 1007 513 – 896 48 – 214

Industrial Park 537 309 – 438 43 – 99

Belvedere 980 590 – 840 60 – 169

Mountain Pine n/a 405 – 586 46 – 136
North

The Ouachita System or Zone makes up the largest percentage of the total water
distribution system. The area on the south side of the City and south of Lake
Hamilton in general are included in the Ouachita Zone including to the west and
east outside of the City limits. Generally, these are the lowest ground elevations
in the system excluding the Industrial Park Zone.

Figure 11 shows the existing pressure zones across the distribution system.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 24

Figure 11 - Existing Pressure Zones Map 25
City of Hot Springs – Water System Master Plan | Crist Engineers, Inc.

Water storage in the Ouachita

Zone consists of four (4) storage

tanks. A 3,000,000-gallon ground

storage tank referred to as the

Music Mountain Tank, a 500,000

gallon elevated multi-column

storage tank known as the

Highway 70 West Tank, a

1,000,000 gallon elevated storage

tank known as the Hollywood

Avenue Tank, and a 730,000 Figure 12 - Music Mountain Ground Storage
gallon standpipe known as the Oak Tank

Grove Tank. The Music Mountain

Tank is located off Mt. Tabor Street and Sour Rock Springs Road north of Albert

Pike Road, east of Lake Hamilton.

The Highway 70 West tank is located north of

Highway 70 West off Standpipe Drive. The

Hollywood tank is the most centrally located tank

in the system and is located on Hollywood Avenue

between Central Avenue and Malvern Avenue.

The Oak Grove Standpipe is located off Forest

Ridge Road, south of Highway 270 West and west

of Lake Hamilton and serves the Royal Water

District. These four tanks provide water storage for

the entire Ouachita System with an overflow

elevation ranging from 705 to 710 feet MSL for the

Music Mountain Tank, Hollywood Avenue Tank,

and Oak Grove Tank. The Highway 70 West Tank

has an overflow elevation of 687 feet MSL, 18 feet

lower than the other water storage tanks in the

Ouachita Zone. Figure 13 - Highway 70 Elevated
Storage Tank

Finished water is pumped into the Ouachita Zone from the high service pumps
located at the Ouachita Water Treatment Plant (OWTP). These pumps are
controlled by the water level in the Music Mountain Tank. The Highway 70 West
tank level is controlled by an altitude valve at the base of the tank. This altitude
valve prevents the tank from overflowing but will allow water to exit the tank if the
pressure gradient around the tank drops low enough. Because of the lower

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 26

overflow elevation of this tank, during periods of normal water demand the
Highway 70 West tank stays submerged. In other words, the tank stays full and is
unable to draft or let water back into the system.

Most of the water flow to the Hollywood tank is controlled by a solenoid actuated
flow control valve (FCV) located in the existing Hollywood PRV vault near
Hollywood park. This valve allows water from the higher elevated Twins Zone to
enter the Ouachita Zone by means of gravity and 164-foot difference in hydraulic
grade line. This valve is automatically controlled by the water level in the Hollywood
Avenue Tank through SCADA. It operates off predefined user input set points
similar to the high service pumps. The existing PRV valve located in this vault was
upgraded, retrofitted, and added to the City’s SCADA system in 2016.

The Lowery Street PRV, Pleasant Valley PRV, and
Keuka PRV’s are still in operation, but are set to
only open in the event the Hollywood tank level
falls below a certain level and cannot be
maintained by the Hollywood flow control valve
alone. The Lowery Street PRV is in the north lane
of Malvern Avenue near the intersection of Lowery
Street. For this reason, gaining access to maintain
the valve is problematic. The Pleasant Valley PRV
(pictured) is located on the south side of the intersection between Cones Road and
Pleasant Valley Street. According to City staff, the Pleasant Valley PRV along with
the Keuka PRV cannot be adjusted to a low enough setting to prevent water from
always passing through the valve. In other words, these PRV’s constantly allow
water to “leak” or enter the Ouachita Zone from the Twins Zone.

Most of water flow to the Oak Grove Tank is controlled by a solenoid actuated flow
control valve (FCV) located southeast of the Crystal Hill and Treasure Isle Road
intersection. This valve is automatically operated via the City’s SCADA system
based on the water level in the Oak Grove Tank. The second entry point that allows
water to flow to the Oak Grove Tank is the Mountain Pine South PRV.

Finished water is also pumped into the Holly Street Zone from the high service
pumps located at the Lakeside Water Treatment Plant (LWTP). Water storage in
the Holly Street Zone is provided by a 2,000,000-gallon concrete ground storage
tank and a 250,000-gallon standpipe. The overflow elevation of the Holly Street
ground storage tank is approximately 876 feet MSL and the Woodmere standpipe

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 27

has an overflow of 869 feet
MSL. The Holly Street tank
shown in Figure 15 is located
north of the downtown area
and Holly Street. The
Woodmere tank is located on
Woodmere Street off
Whittington Avenue. The
HSP’s are manually operated
to maintain the water level in
the Holly Street Tank. The Figure 14 – Lakeside WTP High Service Pumps
Holly Street system generally
serves the downtown area north of West Mountain and north of Hot Springs
Mountain. This includes all of Whittington Avenue west of the fountain to
Blacksnake Road and all of Park Avenue east of the fountain to Stonebridge Road.

Figure 15 - Holly Street Ground Storage Tank

The Twins system makes up the second largest percentage of the total City’s water
distribution system and covers most of the north side of the City along with the

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 28

downtown area. Water storage in the Twins Zone is comprised of two 3,000,000-
gallon concrete ground storage tanks shown in Figure 16. The Twin tanks known
as the “Twins” are located on the south side of West Mountain north of the Airport
Road and Albert Pike Road Intersection. These tanks have an overflow elevation
of 869 feet MSL. Water is pumped directly into the Twins system from the Music
Mountain pump station located at the base of the Music Mountain tank. Currently,
water is also allowed to flow into the Twins system through the partially opened
valve on Whittington Avenue. A boundary map of the existing pressure zones is
shown in Exhibit 1.

Figure 16 - Twins Ground Storage Tanks

The 16-inch gate valve located near the intersection of Whittington Avenue and
Pine Street is an isolation valve known as the Whittington valve and has been used
for many years as a manually operated flow control valve. The valve is partially
opened and partially closed by City staff to allow water to leave the Holly Street
system and flow into the Twins System as needed. The valve is adjusted to control
the amount of water leaving the Holly Street Pressure Zone. The amount of turns
the valve is opened is dependent upon water usage in the system. Current
operation of this valve allows water to constantly “leak” or enter the Twins system
from the Holly Street system, which is from the Lakeside Plant.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 29

Water is pumped from the Ouachita zone into
the Crystal Springs zone by the Royal pump
station located along Highway 270 West. This
booster pump station includes three (3) pumps
that pump water to the Crystal Springs Tank.
The 400,000-gallon water storage standpipe is
in Crystal Springs south of Highway 270 west,
along South Crystal Springs Road. The water
level in this tank is maintained by the Royal
pump station. The 1,007 feet overflow elevation
for the Crystal Springs system is the highest
overflow elevation in the water distribution
system. The terrain across this entire region Figure 17 - Royal Pump Station
varies; however, the highest customer service
elevations are in the Crystal Springs system.

The Industrial Park system has an overflow
elevation of 537 feet MSL making it the lowest
elevated zone in the water distribution system.
A 250,000-gallon elevated water tank provides
water storage for this system. The Industrial
Park Tank is located off Industrial Park Drive
southeast of Hot Springs. Water flows by
gravity from the Ouachita system into the
Industrial Park system through a PRV. The
pressure setting on the Industrial Park PRV is
set to the overflow level of the Industrial Park
tank. Like the Highway 70 West tank, the
current PRV setting causes this tank to
continuously remain submerged. In other
words, the tank is always full, since the Figure 18 - Industrial Park Elevated
surrounding system pressure is higher than Storage Tank
the pressure produced by the tank; therefore,
water cannot exit the tank unless system demands increase enough to lower the
surrounding system pressure.

Water is pumped from the Holly Street system into the Belvedere system by the
DeSoto pump station. The DeSoto pump station is located adjacent to DeSoto
Park, northeast of the Park Avenue and Gorge Road intersection. The Belvedere
tank is a 300,000-gallon steel ground storage tank with an overflow elevation of

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 30

980 feet MSL. The pumps in the DeSoto pump station are controlled by the
Belvedere tank level through the City’s SCADA system.

An emergency connection located on Fox Pass Road off Highway 7 connects the
Belvedere system to the North Garland County Rural Water District water system.
This emergency connection is normally closed.

The Mountain Pine North system is fed by a two PRVs located on the east side of
Mountain Pine Road, just north of the Mountain Pine junction. The Mountain Pine
North system is supplied by the Ouachita system. The pressure setting on this
valve is set to 125 PSI. The main function of this PRV is to reduce the high
pressures water users would experience as a result from being connected to the
main transmission line from OWTP to Music Mountain. For future planning
purposes this valve should be located, maintenance performed and pressure
settings verified and confirmation that pressure gauges are functioning properly.

Figure 19 shows the general location of all active water storage tanks in the City’s
distribution system. Figure 20 includes a water distribution process flow diagram.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 31

Figure 19 - Vicinity Map - Water Storage Tanks

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 32



Figure 20 - Water Distribution Process Flow Diagram

City of Hot Springs – Water System Master Plan | Crist Engin

neers, Inc. 33

B. Inventory of Existing Water Pipes

The water transmission capacity of a pipeline is dependent upon the pipe diameter
and relative roughness of the pipeline. For a given flow through a pipe, the head
loss through that pipe increases as diameter decreases and the roughness factor
decreases. It is important that the pipes within a distribution system are properly
sized to prevent unnecessary head loss. The roughness of a pipe can vary
considerably with pipe material, age, and the condition of the pipe.

Water transmission mains can be thought of as interstates or highways for water
to travel. In general, water pipes greater than or equal to 10-inch diameter are
normally considered transmission lines. Smaller diameter pipes are considered
distribution or service lines.

Table 8 shows the quantities of 2-inch diameter piping and larger within the City’s
water distribution system. The total system consists of over 4.5 million feet, or 868
miles, of distribution piping. The Ouachita Pressure Zone is the largest with 56%
of the total system piping.

Figure 21 - Cast Iron Pipes

The old 6-inch cast iron pipe pictured above was removed from service in 2014.
When compared to a new pipe, the old pipe will have a lower roughness coefficient
because of the internal roughness on the pipes surface. This fouling growth on the
surface of the pipe causes a decrease in the effective diameter of the pipe resulting
in reduced hydraulic capacity.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 34

Table 8 - Distribution Pipe Inventory

Distribution Pipe Inventory
Hot Springs, Arkansas

Pressure Zone

Pipe Diameter Total
Ouachita System
Twins
Lakeside /
Holly
Ind. Park
Belvedere
Crystal
Springs
(1007)

Percent of Total

Pipe Length (Linear Feet)

2" 892,745 353,750 60,233 14,251 958 56,465 1,379,217 30%

3" 1,173 - - -- - 1,173 0%

4" 66,612 9,004 2,231 2,049 1,719 33,398 114,633 3%

6" 1,367,869 340,146 53,490 28,445 6,603 64,417 1,856,095 41%

8" 347,180 109,731 1,833 10,645 3,313 22,096 495,544 11%

10" 30,809 15,521 11,646 3,093 - 28,154 89,461 2%

12" 363,577 72,403 34,973 5,211 11,155 - 483,965 11%

14" 1,928 - - -- - 1,928 0%

16" 84 16,624 8,978 - 3,438 - 28,624 1%

20" 12,809 6,101 73 - - - 18,985 0%

24" 61,616 17,292 - -- - 78,909 2%

30" 32,831 - - -- - 32,831 1%

TOTAL 3,179,234 940,148 1,106,721 63,694 27,185 204,530 4,581,364 100%
1% 4% 100%
% of 69% 20% 4% 1%
Total

*Quantities taken from InfoWater Model

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 35

C. Pumping Facilities

The City has five water pumping facilities. Water is pumped into the water
distribution system from the high service pumps (HSP’s) located at both the
Lakeside and Ouachita water treatment plants. Water from the OWTP is pumped
in the Ouachita Pressure Zone and then again pumped from the Ouachita
Pressure Zone into the Twins Pressure Zone by the Music Mountain Pump Station.
Water is also pumped from the Ouachita Pressure Zone into the Crystal Springs
Pressure Zone. Water from the LWTP is pumped in the Holly Street Pressure
Zone. Water is also pumped from the Holly Street Pressure Zone into the
Belvedere Pressure Zone.

Figure 22 shows the high service pumps located on top of clearwell #3 at the
OWTP.

Figure 22 – Ouachita WTP - High Service Pump Station

An overview of the active pump stations within City’s distribution system is shown
in Table 9. The pump station located on Pine Street is not listed in Table 9, since
it is normally not active. The Pine Street pump station contains only one pump and
was constructed to fill the Holly Street Tank when the LWTP needs to be taken
offline for routine maintenance or an emergency. With LWTP out of service the
Pine Street pump station provides the City with a redundant way to fill the Holly
Street Tank. Under current conditions, an emergency would exist if the LWTP was
offline or unable to pump for an extended period to maintain the water level in the
Holly Street Tank. The Holly Street Tank supplies the DeSoto pump station which
supplies the Belvedere System. From a reliability standpoint, with the LWTP
offline, the one pump located in the Pine Street pump station is not considered a
redundant supply of water.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 36

Table 9 - Overview of Existing Pump Stations

OVERVIEW OF EXISTING PUMP STATIONS

LOCATION / # OF BACKUP HORSE- BASE DESIGN DESIGN *FIRM
DESCRIPTION PUMPS POWER POWER ELEV. HEAD FLOW PUMPING
(FT) (GPM) CAPACITY
(FT)
(GPM)
OWTP - High 4 YES (2) - 450 HP 472.5 420 / 350 3400 /
Service Pump (2) - 600 HP / 280 4100 / 14,600
4600
Station 420 / 350 2,777
/ 280 4000 /
5600 / 9,100
6500
475**
LWTP - High 3 YES (3) - 350 HP 599 310 3000
Service Pump 5
4 YES (3) - 150 HP 672.8 193 2500
Station (2) - 250 HP 210 3200

Music NO (4) - 7.5 HP 597 137 150
Mountain -
Pump Station

Belvedere /
Desoto Pump

Station

Royal Pump 3 YES (3) - 40 HP 513 356 300 520**
Station

*Firm Pumping Capacity - Pumping capacity with the largest pump reserved as standby unit.
**Values estimated from hydraulic model.

It is recommended that all pump stations have the capacity to meet 125% of
maximum day demand at all times with the largest pump reserved as a standby
unit. Tables 10, 11, and 12 show each pump station’s firm pumping capacity versus
the current and future maximum day demand from each pump station’s respective
zone, and subsequent downstream zones. For example, Ouachita HSP station
must be able to pump the maximum day demand for all zones excluding the Holly
Street Zone and the Belvedere Zone.

A quarter of the demand from the 705 Zone has been added to the Music
Mountain Pumping Station. This is to account for the volume of water passing
through the Twins Zone back into the Ouachita (705) Zone.

Table 10 - Pump Station Capacity - Current Maximum Day Demand

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 37

PUMP STATION PUMPING CAPACITY EVALUATION

1CURRENT MDD

Location / Downstream Max Day 1.25 X Firm Deficiency Surplus
Description Zone Demand Max Day Pumping (GPM) (GPM)
Demand Capacity
OWTP - High (GPM) 2,046
Service Pump 632
705' 396
Station
869' 15,448 19,310 14,600 4,710
LWTP - High
Service Pump 537'

Station 1007'

Music Mountain 876'
Pump Station 585 731 2,777

980'

869' 6,775 8,468 9,100
(1/4) - 705'

Belvedere / Desoto 980' 64 79 475
Pump Station

Royal / Hwy 270 1007' 312 390 520 130
Pump Station

1Current Maximum Day Demand = 23.08 MGD

Based on the criteria of providing pumping capacity equal to 125% of the maximum
day demand, Table 10 indicates that all existing pump stations except for the high
service pumps at the Ouachita WTP have sufficient pumping capacity under the
current maximum day demand conditions. The OWTP high service pumps cannot
meet MDD x 1.25 even at current demand and certainly not for the projected
demand from future years as shown in Tables 11 and 12. Therefore, additional
capacity is required.

The planned Amity Road Water Treatment Plant (15 MGD) as described in the
Water Supply Study (Lake Ouachita Project) will provide additional pumping
capacity to offset this pumping deficit.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 38

Table 11 - Pump Station Capacity - 2030 Maximum Day Demand

PUMP STATION PUMPING CAPACITY EVALUATION
2030 MAXIMUM DAY DEMAND

Location / Downstream Max Day 1.25 X Firm Deficiency Surplus
Description Zone Demand Max Day Pumping (GPM) (GPM)
(GPM) Demand Capacity 1,870
1,898
OWTP - High 705' 18,584 23,230 14,600
Service Pump 869' + 379
537'
Station 10,500 =
1007' 25,100
+

New Amity Rd.
WTP

LWTP - High 876' 704 879 2,777
Service Pump 980'

Station

Music Mountain - 869' 8,149 10,187 9,100 1,087
Pump Station (1/4) - 705'

Belvedere / 980' 76 96 475
Desoto Pump

Station

Royal / Hwy 270 1007' 375 469 520 51
Pump Station

It is assumed, for the purposes of this evaluation, that the planned Amity Road
Water Treatment Plant (15 MGD) will be placed in service prior to the 2030
evaluation as shown in Table 11. Table 11 indicates that the Music Mountain Pump
Station is the only pump station to have pumping capacity deficits under the 2030
future demand conditions. With the improvements outlined in the CIP, the
downstream demand of the Music Mountain Pump Station will be reduced.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 39

Table 12 – Pumping Station Capacity - 2040 Maximum Day Demand

PUMP STATION PUMPING CAPACITY EVALUATION
2040 MAXIMUM DAY DEMAND

Location / Downstream Max Day 1.25 X Max Firm Pumping Deficiency Surplus
Description Zone Demand Day Capacity (GPM) (GPM)
(GPM)
Demand 592

OWTP - High 705' 19,606 24,508 14,600 1,849
Service Pump 869' +
537' 374
Station 1007' 10,500 = 26
25,100
+

New Amity Rd.
WTP

LWTP - High 876' 742 928 2,777
Service Pump 980'

Station

Music 869' 8,600 10,750 9,100 1,650
Mountain - (1/4) - 705'
Pump Station

Belvedere / 980' 81 101 475
Desoto Pump

Station

Royal / Hwy 1007' 396 494 520
270 Pump

Station

It is assumed, for the purposes of this evaluation, that the planned Amity Road
Water Treatment Plant (15 MGD) will be placed in service prior to the 2040
evaluation as shown in Table 12. Table 12 indicates the pumping capacity deficits
under the 2040 future maximum day demand conditions. The Music Mountain
pump station has pumping capacity deficits under the 2040 future maximum day
demand scenario. This pumping deficit will be reduced if certain distribution system
improvements as outlined in the CIP are implemented.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 40

Recommended Improvements

• It is recommended that several improvements be made to the pump stations
throughout the distribution system.

• One suggested improvement includes the replacement of the emergency
Pine Street Pump Station with a new booster pump station. This
improvement will be needed to take the LWTP offline. The new pump station
will provide enough pumping capacity to serve the Holly Street System and
downstream Belvedere System. The pumps would be controlled by the
water level in the Holly Street Tank. Multiple pumps will be installed to add
redundancy and reliability to the downstream systems. As of this writing, the
replacement of the Pine Street Booster Pump Station is in progress.

Figure 23 – Existing Pine Street Pump Station

• The DeSoto pump station does not have an emergency generator to provide
backup power. It is recommended to install an emergency generator at the
DeSoto Pump Station.

• It is recommended that a flow meter be installed at the Royal Pump Station
and the flow reading be added to SCADA. The reading from the existing
flow meter at the DeSoto pump station should also be added to SCADA with
trending made available. The ability to view instantaneous flow rates and
observe trend graphs will further assist the City in accounting for
unaccounted for water and future planning efforts.

City of Hot Springs – Water System Master Plan | Crist Engineers, Inc. 41


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