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San Antonio Necua |
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| Water
System |
San
Antonio Necua is a Kumiai Indian community with some 60 families (or
service connections) with a total population of approximately 195.
The community is located in the northern Guadalupe Valley, south
of Tecate and east of Ensenada in Baja California, Mexico. The community obtains its drinking water
from two springs; the water is transported by 3 inch PVC piping for
several miles from the mountains to two concrete storage reservoirs and
from there is distributed to the community.
Although there is fencing around the main stream, the smaller
stream is exposed to the environment and is commonly used by cattle,
coyotes and other animals, and sometimes humans.
The water produced by the streams is not treated or filtered.
The piping is connected to a small concrete reservoir, 3000
gallons (7’ x 7’x 8’), which delivers water to a few homes and
then the remaining water is delivered to a second concrete reservoir of
12,000 gallons (20’ x 20’ x 4’) which is delivered to the rest of
the community via gravity through 2 inch PVC pipe distribution system.
On the north side of the community in the
valley area, the community uses a drilled well for agricultural
irrigation. In August 2004, the well was sounded for water levels and it
was found that the majority of the water is coming into the well at
about 70 feet with the bottom of the alluvial aquifer at 75 +/- 5 feet.
Depth of the well according to on-site documentation is 160 feet.
Pumping water level was 145.4 feet.
It was recommended that the well production be decreased since
the pumping water level is only 15 feet above the pump.
This is necessary in order to prevent the pump from burning out.
Production should be lowered at least 50 gallons per minute (gpm).
It was estimated that the well was pumping at approximately 200
gpm, although the pressure gauge and flow meter were not working at the
time. Approximately 50% of the homes have water piped to
their home (via kitchen sink); the remaining residents have to haul
their water and store it in 55-gallon drum containers inside their
house. Approximately 75% of
the community experiences water outages throughout the year.
The outages occur during peak use times and during drought
conditions. The homes that
experience the most outages are the homes furthest from the reservoirs. The incidence rate of diarrheal cases in the
community, from September 13, 1998 to October 10, 1998, was 366 per
1,000 persons and the incidence rate of highly credible gastrointestinal
illness was 446 per 1,000 persons.
In comparison, the incidence rate of diarrheal diseases in
established market economies (i.e. U.S., Canada, and Sweden) in 1990 was
209 per 1,000 persons for all ages, and for ages greater than 4 years
was 100 per 1,000 persons (Coates Hedberg, 1999).
Water quality data obtained since January 1996 has
consistently shown the presence of total and fecal coliform bacteria (Wilken
Robertson, 1996). The
following table is a brief summary of water quality monitoring of the
distribution system; additional samples taken in the past years have
shown similar water quality results.
na
– not analyzed * NOTE: Microbiological data generated by the JA JAN Coalition with the assistance of CUNA, Aqualink, and trained community members The
water system spring sources are unreliable and contaminated with total
coliform and E. coli bacteria. Water sampling of the water system has
consistently shown bacteriological contamination.
Analytical testing and a sanitary survey have determined that the
continuing cause of the contamination appears to stem from the water
sources. The community
water supply is unreliable and is subject to water outages that may
allow additional contaminants to enter the water supply.
Drinking water with coliform and E. coli bacteria is a health
risk and could cause serious illness.
Additionally, the storage tanks were built
at a low elevation, thus not allowing for adequate system pressure
(<20psi). The tanks also do not act as storage as the water source
supply is in greater demand. Visual
inspection of the inside of the second reservoir revealed significant
algae growth and the presence of larvae.
The roof of the concrete reservoir had significant cracks and
areas where rain water would pond. Water System Improvement Recommendations The proposed solution to improve the water system would be to construct a water supply well, chlorination treatment, new storage reservoir, and a new water distribution system. This would replace the current contaminated drinking water supply with a water supply that meets drinking water standards and will also provide a reliable water supply. The existing water system could be diverted for agricultural and irrigation use within the community. This community has electricity.
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