20060803DEQ letter to EAG.pdf

STATE OF IDAHO
DEPARTMENT OF
ENVIRONMENTAL QUALITY
RECEIVED
1410 North Hilton. Boise, Idaho 83706 . [phone]
200& AUG -3 AM 8:
\O/\HO pu~t Ie:
UTtLiTIES CO~IIMISSION Dirk Kempthorne, Governor
Toni Hardesty, Director
TSCPE-147/2006
July 27, 2006
Robert DeShazo
Eagle Water Company, Inc.
172 W. State Street
Eagle, Idaho 83616
A- b- UJ '-C)..S-:-
RE:Eagle Water Company Preliminary Engineering Report (Eagle, Ada County)
Dear Mr. DeShazo:
The engineering report for Eagle Water Company has been reviewed. To ensure that construction will meet state
drinking water rules and the Recommended Standards for Water Works (RSWW), please address the following
comments:
1. The report shows that average annual demand from the combined residential, commercial, and irrigation
sources was calculated by using actual demand data obtained from 2002 through 2005. The drawings
indicate that this system is designed to provide fire flows. However, the report does not give the fire flow
demand for the residential or commercial units.
a. Please show the total demand of the system that accounts for the residential, commercial, irrigation
and fire flow demands. Then, provide an analysis of how the system meets/does not meet these
flow demands given the available wells and storage tankslbooster pumps.
b. If the system has more than one pressure zone, the report must provide information on the demands
and source and/or booster pump capacity of each pressure zone. With the largest source/and or
booster pump out of service, the report must demonstrate that the remaining sources and/or booster
pumps are capable of meeting the peak hour demand (which includes irrigation and all other
demands) plus fire flow for each pressure zone.
c. Peak factors for maximum daily demand (l.8X average daily demand) and peak hourly demand
(2.85X average daily demand) were obtained from a reference text. The Appendix has actual data
from which the peak factors may be estimated. Since actual data are available, then those values
must be used. For example, the estimated peak day demand using the average consumption from
the month of July is 4376 gpm. The average daily demand is shown to be 1259 gpm. Therefore
the peak factor for the maximum day demand is about 3.5X the average daily demand using actual
data. Please note the following related comments:
1. The previous sentences and calculations assume that the average daily flow during July is
the same as the peak day, which is typically not true. Please provide either specific data to
indicate what the peak days have been, or provide a reasonable peaking factor.
11. Have you any actual data that indicates what factor should be used to determine peak hour
on peak day?
Robert DeShazo
!u\'j '2.1 , 2~~6
Page 2 of 4
d. What are the fire flow requirements for the residential and commercial buildings? Please provide a
statement from the fire marshal specifying the required fire flows for the residential and
commercial units.
2. If available, please provide the well logs/tests for each well. . Please verify the sustainable capacity of each
well in the system and that the pumps are set at or below those capacities.
a. Well #4 appears to be the largest source with a reported capacity of 3046 gpm and has a variable
speed pump. However, the report that accompanied the well house and equipment plans showed
that Well #4 has a sustainable flow of about 2500 gpm.
b. The models are set-up so that Well No.1 (pMP-l assumed to be Well #1) is set above 560 gpm
(the reported sustainable capacity): 719.79 gpm, 615.34 gpm, 771.25 gpm, 719.8 gpm. Does Well
#1 typically provide outputs at these rates, which are above the reported aquifer capacity?
3. Please list the status of defects or deficiencies, such as pressure zone problems, including existing
population and households affected. Deficient pressure zones must be distinctly shown on the maps and
must include both peak hour and peak hour plus fire flow.
4. In the discussion of the WaterCAD modeling results for the conditions before 2006, it states that 13 hydrant
flow tests were used. The field data were taken at different times from 2002 to 2005. Eleven of the model
results had pressures that were one to 37 psi higher than the field data, while two were 20+ psi lower than
the field data. However, four of the points were excluded from the analysis of the results because they
were extreme values, i.e. model values that were extremely high or low compared to the field data.
a. Those extreme values cannot be excluded from the results. The goal of the calibration is for the
model to represent the actual system as closely as reasonably and thus have pressure results that are
also reasonably close to actual field data, at least be within :!:10 psi. Instead of excluding the
outliers , the model configuration should be evaluated for errors in the model set-up and physical
problems in the distribution system itself, such as partially closed valves or lines that are smaller
than those used in the model. Finding and fixing errors in the model or physical system may bring
the results closer to the field data. Poor calibration of the model would lead to models of future
scenarios that may not be representative of the system.
b. The hydrant flow test model result only shows eight points. The report indicated that there were
four points that were excluded. Please add the ninth hydrant test that seems to be missing from the
table.
5. There are five (5) sets of WaterCAD model results: two for the Pre-2006 conditions and three for .the
Present 2006 scenarios. Please provide further clarification of the scenario differences between the
multiple results. Models must be run to demonstrate that the system is able to maintain a minimum pressure
a. 40 psi during peak hourly demand conditions, excluding fire flow, throughout the distribution
system (IDAPA 58.01.08.552.01.b.i), and
b. 20 psi during peak hourly demand conditions plus fire flow throughout the distribution system
(IDAP A 58.01.08.552.0 l.b.ii)
Robert DeShazo
July 27, 2006
Page 3 of 4
6. Despite the addition of the 2000+ gpm pump, there are areas where pressures are still less than 20 psi (peak
hour demand plus fire flow), while other areas have pressures that are slightly over 100 psi. Static pressure
in the distribution system must be kept below 100 psi and ordinarily should be below 80 psi (IDAP A
58.01.08.552.01.bjii).
It appears that a pressure safety reducing valve station will be added along Floating Feather Road. The
100+ psi pressures appear to occur in the area between Pebble Beach Way and Edgewood Lane, north of
Cerramar Court. Is this where the proposed pressure safety reducing valve vault is supposed to go? This
should be specified in the report and included in a map for the proposed improvements to the system. Also
155 through J-199 have pressures above 80 psi, with some junctions exceeding 100 psi. These junctions
are along State Street between Ballantyne Road and Eagle Road. Should this area have a pressure reducing
valve station as well?
7. The report states that future scenarios were not modeled "
. ..
due to the positive results obtained in the
Present Conditions 2006 Scenario analysis . This contradicts the statement, "The need for additional
supply remains to this day." The results of this scenario show that there are still areas with deficient
pressures (less than 20 psi under peak hour conditions plus fire flow) despite the system enhancements of
Well #7 and the 2000+ gpm booster pump station. If this report is to serve as a preliminary version of a
master plan, then it must address future scenarios.
8. Per the previous comment, a model for future scenarios in the next 20 years seems to be warranted. The
report must include the proposed additions to the system that would allow the system to meet the future
demands and requirements. At what point will EWC need to increase its source capacity to meet the
increasing demand? Forecast of demand must include residential, irrigation, commercial, industrial and
fire flows. Maps, site plans, figures, and tables can be used to complete this section. Maps must clearly
show the locations of proposed system improvements. See comment #6.
9. The Idaho Power Company has provided a letter to certify that Well #7 will have access to Grids #2 and #4
for backup power. However, the backup capability between the two grids is not available during peak
periods in the summer. Furthermore, there is no elevated storage to maintain system pressures in the event
of a power outage and there is no automatic transfer between the two power grids to guarantee
uninterrupted service. To avoid system depressurization and comply with current standby power
requirements, Eagle Water Company must install dedicated standby power with automatic transfer
capability as indicated below:
a. Provide standby power for all new sources and booster stations including the newest source, Well
#7.
b. Provide standby power for sources or booster stations that must be modified to serve additional
connections. For example, DEQ will not approve new subdivisions in a system or pressure zone if
pumping capacity is inadequate with the largest pump out of service. Standby power must be
provided as part of the modification to increase pumping capacity.
c. The report must evaluate all existing sources and booster stations with regard to standby power
deficiencies. If there are no proposed expansions related to particular facilities, DEQ does not
require the addition of standby power to existing facilities. Put another way, non-growing systems
are "grandfathered" with regard to required improvements. However EWC should notify
customers of deficiencies, possible ramifications, and the estimated rate increase it would take to
upgrade the system. If customer expectations are high enough, EWe should then contact the Idaho
Public Utilities Commission to discuss the issue further.
"--'"'---"
Robert DeShazo
July 27, 2006
Page 4 of 4
10. Unless there is a large excess capacity of sources and/or booster pumps for the entire system and for each
pressure zone, then a Declining Balance Report will need to be submitted with each proposed addition.
The Declining Balance Report must match the approved engineering report. The form for the Declining
Balance Report must be accepted by the DEQ.
11. At your convenience, DEQ proposes a meeting to discuss these connnents, as well as have the opportunity
to have your assistance in clarifying items on the WaterCAD model results and items in the report that do
not appear to be immediately obvious to the reviewer.
Please call me with any questions at [phone], or contact me via e-mail at diane.bacongui~deq.idaho.gov
Sincerely,
)Jt
p().(!
01'\j)
Diane Baconguis, E.~.
IDEQ Technical Services
DB:sjt
Charles W. Ariss, P.E., Regional Engineering Manager, DEQ Boise Regional Office
James Rees, P., MfC, Inc.
Tiffany Floyd, Regional Drinking Water Manager, DEQ Boise Regional Office
Monty Marchus, P.R, DEQ Boise Regional Office
Michael Stambulis, P., DEQ Teclmical Services
Mark Clough, P .E., DEQ Teclmical Services
Source File 2, Eagle Water Company Preliminary ER
TSCPE Reading File