PROPOSED GROUNDWATER RESOURCE ASSESSMENT AND DRILLING AND
CONSTRUCTION OF DEEPWELL IN SAPANG BATO, ANGELES CITY
Or
PROPOSED GROUNDWATER RESOURSE ASSESSMENT AND DEVELOPMENT AND
CONSTRUCTION OF DOMESTIC WATER RESOURCE SYSTEM
When the US military withdrew from Clark Air Force
Base, the United States failed to identify and clean up dozens of contaminated
sites. At present, thousands of residents are potentially exposed to
unremediated toxic hazards which maybe responsible for serious health problems
found in those areas. Of particular concern is the contamination of groundwater
upon which communities surrounding the former base are dependent for drinking,
cooking, bathing and washing. A� 1996
survey conducted by the International Institute for the Concern of Public
Health�� and Peoples� task Force for
Bases Cleanup� revealed that 13(?)
communities around the former military base reported high levels of kidney,
urinary, nervous and female system health problems.The highest prevalence� of these problems occurred in communities
closest to or on base and highly contaminated sites. The study emphasized that
� the water situation, as it currently exist for these barangays, is a likely
source of some of these health problems�.
Also, in 1997(?), the Clark Development Corporation
commissioned Weston International, a US environmental firm, to conduct an
environmental baseline study of� the
soil and water at Clark. Toxic substances were found in both water and soil
samples. Most of the chemicals are carcinogenic or are associated with other
serious health problems like birth defects, miscarriages and central nervous system
disorders.
Community Profile of Barangay Sapang Bato as adapted
from the Health for All Survey
Barangay Sapang Bato is one of the three small
barangays� which is on the western edge
of the base, where the Civil Engineering Entomology, Power Plant and the Wagner
Aviation Transformer Site were located. According to the 1997(?) Weston
International Soil Baseline Study, dieldrin, heptachlor, petroleum products and
polychlorinated biphenyls� all exceeded
the US Environmental� Protection� (EPA) Region III Risk Based Concentrations
for Soil Ingestion in at least one sample on those sites. At the Civil
Engineering Entomology site, the pesticide dieldrin exceeded the industrial
Risk Based� Concentration (RBC) standard
by over five times.
The barangay is located southwest of the base,
adjacent to the former civil engineering area ( should
we also add that a part of� it is uphill
or elevated relative to the base). It is also within the vicinity of the
family house area and the POL (petroleum, oil, lubricant) storage area. Spills
had been reported along the POL pipeline and petroleum hydrocarbon
contamination is suspected. The northwest tip of the area is downgradient to
the POL storage area.
It is also adjacent to the former vehicle maintenance
complex. There is potential exposure from wood preservatives from the chemical
treatment of lumber/wood for construction use. The site was also used as a
warehouse for asbestos foams and other road building materials.
As of today, these communities are still utilizing the
same water system as they used when the health survey took place. Recently,
Clark Development Corporation hooked the two of these communities on their� water supply which quality is also in
question
Because of the inaction of both the Philippine and
the US governments in addressing the problem, providing clean and safe supply
of� water has been identified as one of
the remedies to initially address many of these health problems.
.
Therefore, this proposal outlines the terms of
reference for the conduct of groundwater resource assessment and development of
a deepwell source of domestic water in Sapang Bato, Angeles City. This project
also includes water quality sampling to determine the suitability of the water
source and any contamination� in the
upper layers that will require preventive jacketing around the well housing to
prevent the transmissions of toxins between the water bearing layers.
As confirmed by Clark Development Corporation (CDC)�s
hydrogeologist, there are several layers of aquifer underlying Clark field
separated by thick strata of impermeable clay protecting the deeper layers from
contamination. It is presumed that the deepest of these aquifers contains the
water most likely free of toxins.
�
The project aims to:
� Define the hydrogeological condition of the
project area
� Delineate the water-bearing formations within
the project area
� Determine the availability and characteristics
of groundwater within the project area
� Identify criteria and sources of potential
groundwater pollutants, toxic chemicals, ionic
contaminants
and hazard within the project area and formulate measures to mitigate them.
� Identify the potential sites for drilling of
test/observation holes.
� Prepare the preliminary well design and the
general specifications for the drilling and testing program.
� Drill, develop and construct the deepwell.
� Fabricate and construct an elevated water tank
� Lay out distribution pipes
1.
Compilation and review of available geological and
hydrogeological reports and data of the general area.
2.
Field confirmation of established geology and
hydrogeology of the area with emphasis on the distribution, extent and nature of
underlying rocks and geologic structures which may have effect or influence on
the accumulation and movement of surface and groundwater.
3.
Inventory of existing wells and other water points
in the project vicinity to obtain more realistic values of well yield,
permeability and other aquifer characteristics.
The required information
includes, among� others:
� location and depth of existing wells
� well construction details
� well logs
� water level measurements
� pumping test records
� permeability, specific gravity and well yield
� water quality data
� river discharge rate
� recharge zones
4.
Identification of potential sources of groundwater
pollutants, toxic chemicals and ionic contaminants within the target area (such
as industrial waste disposal sites, shallow excavations, septic tanks, crop
fertilizers, pesticides, herbicides and other agricultural chemicals, leaks in
sewers, storage tanks and pipelines and animal feedlots). Existing surface
water and groundwater shall be sampled systematically and analyzed for complete
bacteriological and pertinent� water
chemical analyses.
5.
Conduct geo-resistivity survey to identify
sub-surface rock formation , depths and thickness of each layer on the basis of
gathered/interpreted geophysical data and correlation with local geology.
6.
Preparation of�
preliminary well design that shall indicate the target depth, borehole
and casing sizes and the estimated length of well screen or other form of
alternative casings to be used.
7.
Report maps and diagrams� preparation. A preliminary report shall consist of a summary of
initial findings and recommendations including proposed well site, suggested
well design and general technical specifications for the drilling and testing
of the well. A final draft report shall be submitted to cover methodology,
results of various activities, information, assessment and recommendations on
the groundwater resource development.
��������� A� deepwell shall be
located systematically on the basis of the result of the hydrogeological study.
Thereafter the deepwell will be drilled,�
developed and constructed�
following the predetermined well design. (see Table 1)
The whole project is
estimated to be completed� in
______� broken down as follows:
���������
|
Phase 1 |
Hydrogeological and Geophysical Investigation |
|
|
Phase 2 |
Drilling, Development and Construction of
deepwell (including installation of submersible pump) |
|
|
Phase 3 |
Construction of�
Elevated Water Tank (Phase 2&3 can be done simultaneously) |
|
|
|
|
|
���������
|
Item |
Scope
of work |
Qty |
Unit |
Unit
rate |
Total |
|
1.0 |
Mobilization of drilling unit,all necessary
accessories and staff to the project area |
1 |
No. |
|
|
|
2.0 |
Set-up drilling equipment, supply and
installation of conduction casing |
1 |
No. |
|
|
|
3.0 |
Drilling of f81/2�
pilot hole |
200 |
Lm |
|
|
|
4.0 |
Perform resistivity and self-potential logging in
pilot hole |
1 |
No |
|
|
|
5.0 |
Ream f81/2�
pilot hole to f121/4 borehole |
200 |
Lm |
|
|
|
6.0 |
Supply and install permanent blank casing f8�
B.I. welded pipe |
200 |
Lm |
|
|
|
7.0 |
Furnish and install gravel pack materials in
annular space |
182 |
Lm |
|
|
|
8.0 |
Deffoculate the mudcake with a polyphospate� solution |
1 |
No |
|
|
|
9.0 |
Well development by backwashing,� and surging� |
24 |
Hr. |
|
|
|
10.0 |
Perform constant discharge pumping test of 72
hours duration |
72 |
Hr |
|
|
|
11.0 |
Supply and installation of f38mm G.I. gravel fill
pipe with screw cap |
1 |
No |
|
|
|
12.0 |
Grouting of top casing� and 1 sq.m. concrete pedestal |
18 |
Lm |
|
|
|
13.0 |
Supply and installation of f50mm G.I. water level
sounding tube an done meter stick up |
1 |
No |
|
|
|
14.0 |
Demobilization of equipment, accessories, staff
and clean and site restoration. |
1 |
no |
|
|
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