Provincial Waterworks Authority, Phichit Branch Office (PWAP), is undergoing supplied water
pressure problem, where water pressure is lower than the specified criteria. Water pressure is lower than
7 m when water demand is highest (at 07.00 am). However, when water demand is lowest (at 03.00 am),
water pressure is too high, and that causes high water losses. The reasons are that water pressure at the
source does not relate to water demand, and pipe sizes used in some locations are too small. Therefore,
a new water pressure management is proposed to solve the problem. This study uses the mathematical
model, called EPANET 2.0, to simulate the PWAP network. We collects water pressure data from 11
locations and supplied water quantities from 12 locations. Assessed data from the model are compared
with the field data. It is found that there is 0.16 m difference in average water pressure all the time
(1.19% variation). The objective of this study is to maintain at least 7-meter water pressure all the time
in the studied area while excess water pressure can be reduced when water demand is low. The result
shows that water pressure can be reduced from 16.80 m to 13.79 m. Therefore, the average supplied
water is reduced from 552.88 cu.m/hr to 505.71 cu.m/hr, in which water losses reduce 47.17 cu.m/hr or
5.59% reduction. At the same time, water pressure in the study area can maintain at 7 meter for all time.
To study the hydraulic reliability of pipe networks, first we applied the Resilience Index Ir, of which the
value should range between 0 and 1, but it turns out to have negative values at some time intervals in
this study because at present many customers in some district metered areas (DMAs) receive water
pressure lower than the minimum required level. Moreover, in DMAs 04 and 06 locate farthest, the
value of Ir is higher than 1, meaning that the total water power at inlets of DMAs is severely insufficient.
Thus, in this study, the Standards Compliance (I5) is selected. The results of this research show that the
lowest value of I5 for water users increases when our new water pressure management is applied. The
values of I5 for the present management are lower than 1 in some DMAs, but they are higher than 1 for
all DMAs after applying the new management. In conclusion, by using our new management, water
powers received by water users are higher than the threshold (Pext > Pmin,ext ). This implies that water
users receive both sufficient flow and pressure that meet their demand.