Ammon Fields MPC_Water Study_Update 10.4.2022 1 KA #221128
Technical Memorandum – Addendum
TO: Peter Evans – BCP Development, Inc.
FROM: Riley Bradshaw, PE – Keller Associates, Inc.
DATE: October 4, 2022
SUBJECT: Impacts of Revised Layout on Water Study
ATTACHMENTS: Developer’s Concept Layout Dated 9/13/2022
1.0 PURPOSE OF AMENDMENT
Keller Associates performed a drinking
water system study in September of
2021 for an area of land bounded by
21st South on the south, 52nd East on
the west, 1st Street on the north, and the
Quail Ridge subdivision on the east.
(see Tech Memo dated September 3,
2021 by Keller Associates). The
proposed layout for this development
was changed in September 2022 (see
updated layout figure to the right). This
addendum examines any impacts this
update poses to the previously
completed water study and supersedes
the addendum previously issued in April
2022.
2.0 CHANGES TO ASSUMPTIONS
The changes made to the original layout
include:
• Reduction of commercial area from
8 acres to 5.5 acres (approximate)
• Decrease of overall developmental
density from 4.6 to 4.0 units/acre
• Rearranging of higher and lower
density areas
Figure 1- September 2022 Proposed Development Layout
BCP Development – Ammon Development Water Study April 2022 Addendum
2 KA #221128
• Reduction of the central park location to 4.9 acres from 23.0 acres (approximate)
As shown in the following table, the total number of housing units for the development
decreased as a result of these changes. As a result, the overall maximum day demand (MDD)
and peak hour demand (PHD) for drinking water for the residential areas also decrease (by
approximately 16%). Commercial demands will decrease because of the changes but are
negligible in the overall total, and so have not been adjusted. School areas and demands
remain unchanged.
Table 1 – Changes to Drinking Water Demands
Estimated Household Demand (unchanged):
Max Day Demand (MDD), gpm per unit 0.37
Peak Hour Demand (PHD), gpm per unit 0.49
Units MDD (gpm) PHD (gpm)
Original Revised Original Revised Original Revised
Residential 3,141 2,635 1,167 979 1,530 1,283
Commercial - - 1.1 1.1 1.5 1.5
Schools - - 40 40 50 50
TOTAL 3,141 2,635 1,207 1,013 1,582 1,327
*gpm = gallons per minute
3.0 CONCLUSION
The changes to the proposed layout have the net effect of lowering the total drinking water
demand from what was originally considered. As a result, it is expected that storage tank and
pump capacities would likewise decrease. There is no change to the overall water supply,
storage, and delivery concept that would be pursued for this development. The same
number of wells, tanks, and booster pumps would be required as in the original proposal;
however, the capacity of these facilities would be adjusted during design to reflect the lower
demands to be served.
Additional hydraulic modeling was not performed as part of this addendum. As the location of
churches, schools, parks, and the proposed water storage and pumping facilities are finalized,
the proposed drinking water improvements map found on page six of the original study will need
to be updated accordingly. Hydraulically, the same general approach will apply to pipeline sizing
for this new layout: a 14-inch transmission line running the north-south length of the
development, 10-inch supply lines to schools and commercial areas, 8-inch distribution lines,
and a selection of additional 10-inch and 12-inch lines placed to alleviate low pressures at
higher elevations and to facilitate emergency tie-in with the Quail Ridge subdivision. As noted in
the original study, once local streets are platted, adequate system pressures should be
confirmed through additional hydraulic modeling during design of pumping facilities and before
final design of distribution lines.
LEI PROJECT #:DRAWN BY:DESIGNED BY:SCALE:DATE:SHEET5---REVISIONS4---3---2---1---ENGINEERSSURVEYORSPLANNERS3302 N. Main StreetSpanish Fork, UT 84660Phone: 801.798.0555Fax: 801.798.9393office@lei-eng.comwww.lei-eng.com- A Utah Corporation -NOT
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CITY OF AMMON, IDAHO - A Utah Corporation -DENSITY PLAN EXISTINGGDM/JWA2500125250NORTHSCALE:1"=250'S. 52ND E.1ST STREET LONA NORTH RD 55TH ELOW DENSITY RESIDENTIAL& PARK/GREEN SPACE±534.92 ACHIGH DENSITYRESIDENTIAL±118.45 ACHEAVYCOMMERCIAL±5.48 ACLEGENDLOW DENSITY RESIDENTIALMED-HIGH DENSITY RESIDENTIALHEAVY COMMERCIALPARK / GREEN SPACEBOUNDARY
LEI PROJECT #:DRAWN BY:DESIGNED BY:SCALE:DATE:SHEET5---REVISIONS4---3---2---1---ENGINEERSSURVEYORSPLANNERS3302 N. Main StreetSpanish Fork, UT 84660Phone: 801.798.0555Fax: 801.798.9393office@lei-eng.comwww.lei-eng.com- A Utah Corporation -NOT
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CITY OF AMMON, IDAHO - A Utah Corporation -DENSITY PLANGDM/JWA2500125250NORTHSCALE:1"=250'S. 52ND E.1ST STREET LONA NORTH RD 55TH ELEGENDCOMMERCIALPARK / GREEN SPACER3 (DETACHED / ATTACHED / TOWNHOME)RS LOTS (4-8,000 SF)BOUNDARYROADWAY LOCALROADWAY COLLECTORS. 52ND E.C-1LIMITEDBUSINESSZONE5.48 ACR3118.45 ACRS534.92 ACTABULATIONSOVERALL AREA = 658.85 AC4.0 UNITS PER ACRE = 2,635 UNITSPARK/GREENSPACE