Results of the field investigation are synthesized
as coming from four zones of the basin: I Tropical Dry, II Tropical
Wet, III Coastal Wet and IV Montane Wet (Map
9). Based on these
results, conclusions and recommendations are then made to the IS/DWC,
to PROCUENCA-SAN JUAN, and to the local and national governments
of Costa Rica and Nicaragua.
I Tropical Dry (Lake Nicaragua and its tributaries))
In the SJRB, this entire zone lies within Nicaragua.
With annual precipitation ranging from 750 mm to 2500 mm, and temperatures
between 23ºC and 28ºC (the higher temperatures occur north of the
lake), this zone tends to have tropical grass savannas with ranching
and agriculture (e.g.: rice, corn, wheat, sorghum and beans) as
the main economic activities. There is a low to moderate threat
from hurricanes to the municipalities located along the upper half
of Lake Nicaragua, with a moderately high threat to its northwest
10). The entire zone has a moderate to very severe threat from
drought, and is exposed to short but very heavy rainstorms. Water
sources, which can be drilled or hand-dug wells, rivers, streams,
ponds, and cisterns in the rural areas, and piped water in the urban
areas, seldom go dry. However, they can be affected by heavy storms
and subsequent silting in of ponds and wells.
Most of the population in this zone lives to the
west and southwest of the lake, where poverty levels are not as
severe as they are north of the lake (Map
11). The road network
in the more populated areas is generally good, but in the poorer
zones near the lake, roads are scarce and in generally bad condition.
Consequently, transportation is usually by boats that ply the lake
between population centers.
The zone has been populated long enough so that
the local communities have figured out how to take care of themselves
during extreme meteorological events. As can be expected, however,
problems occur in the poorer communities that are forced to live
in the more precarious situations within the flood plains of rivers
and streams, and in low-lying areas around Lake Nicaragua.
In response to the request from the IS/DWC for
examples of best practices of households and communities used to
cope with climate variability, the following should be mentioned.
It is significant that NGOs play a major part in many of the practices
at this level.
II Tropical Wet (San Juan River and its tributaries))
- Water quality is being protected by reforestation
of the main watersheds and riparian areas.
- Schools and other institutions adopt a river
or stream to keep their water clean and their banks vegetated.
- Environmental education programs are available
in several locations to train local populations to protect water
sources; ground water restoration and management is emphasized
in some of these.
- In communities where ENACAL is not active,
the office of the mayor has staff that work with civil defense
organizations to protect water sources—again usually by reforestation
and forest protection.
- If during a storm floodwater rises significantly
and threatens to contaminate the water source, be it hand dug
well, small pond or cistern, members of the household or the community
channel the excess water away.
- If a water source for a household or community
is threatened by extended drought, water is shared between neighbors.
- When water sources of larger or more fortunate
ranchers go dry in the summer, they move their livestock to a
second property in the mountains where there is sufficient water
- Most of the larger industries have their own
source of water which they maintain, also protecting the forest
cover around the spring, creek or pond.
- Care is generally taken to keep water wells
above sources of contamination such as latrines and corrals.
- All of this is easier to do if the community
or municipality has a water committee; relatively few municipalities
have them, however.
- Municipal governments that find themselves
in charge of the water supply are always looking for new sources.
Generally, they look to exploit new ground water aquifers. If
water becomes scarce during extended droughts, rationing is mandated.
- To prevent future water scarcity, one municipal
government is attempting to increase water capture by tearing
out older dams and allowing the river to flow freely over groundwater
- The same municipality has an emergency plan
that includes coordination with ENACAL in flood or drought emergencies.
- Municipal governments coordinate with one another
and with national agencies concerned with water supply, emergency
response, civil defense, and health.
- During lengthily droughts, water supply agencies
store and release water according to schedules and, during nighttime,
they may close down the system to conserve water.
- All of the national agencies and many of the
local water supply and health service institutions have emergency
- Health workers are aware of the specific diseases
that can contaminate the water supply and become especially bad
as water volume dwindles. Plans and the supplies needed to chlorinate
water sources are in place.
- Water supply institutions have plans, but not
always the resources, to extend piped water services to all neighborhoods.
- In some localities, there are emergency wells
that can be brought on line during extended droughts.
This zone is found almost equally distributed
between Costa Rica and Nicaragua in the SJRB (Map
9). Where human
intervention is minimal, this zone, with an annual precipitation
rate ranging from 2,000 mm to 4,000 mm, is generally covered with
humid to very humid tropical forest—especially on the Nicaraguan
side of the border where communication by land is difficult and
population density falls off rapidly away from the lake. The Costa
Rican side has a history of agricultural intervention (plantations
of sugar cane, rice, citrus, heart of palm, palm oil, banana and
other tree crops), a more complete road network and a higher population
density scattered in small communities. The San Juan River becomes
a major transportation route.
Poverty levels are high to severe (Map
11). Services are minimal and potable water is scarce, especially
just south of the lake along the border. Even the official water
distribution systems are not usable because the aquifer has been
contaminated by pesticides. It is from this zone that many people
from the Nicaraguan side of the border find their way into Costa
Rica. Except for the far north of this zone, flood threat is generally
quite high in both countries, and reaches moderate levels along
the major rivers and just south of the lake (Map
12, Map 13). Hurricane threat
is very low to moderate (Map 10).
During dry periods, the drought threat can be severe.
Rivers and streams, as well as springs and hand-dug
wells, become the drinking water source in rural areas to the south
and downriver from Lake Nicaragua.5Community and municipal
water systems often depend on storage tanks and gravity feed. Except
in the drier parts of this zone, coping with extreme climate variability
is less entrenched; here, many of the inhabitants north of the river
live at a subsistence level and, since their work is to open the
agriculture frontier, many are recent arrivals. Because of this,
coping practices become more the responsibility of municipal authorities
and the health sector than they are to individual households. On
the Nicaraguan side, these institutions are primarily ENACAL, and
SILAIS. On the Costa Rican side, they are AA, and EBAIS.
III Coastal Wet (Indio-Maiz-Tortuguero coastal zone)
- Staff members of all of these institutions
receive training in emergency response.
- During flood emergencies that may affect water
sources in the Nicaraguan portion, SILAIS coordinates the work
of the mayors, the environment ministry, ENACAL and any other
government or non-governmental organization.
- SILAIS has a plan for emergency evacuation
and shelter for areas where flooding is a problem.
- EBAIS has local emergency plans for maintenance
of water supplies to clinics and to affected citizens.
- EBAIS gives talks to its patients on how to
protect water sources.
- SILAIS has equipment to make chlorine and an
emergency environmental health team to treat water in case flooding
contaminates the water sources.
- Communities in Costa Rica generally all have
emergency committees and plans.
- Plans include both preventive measures and
activities of coordination that are initiated and coordinated
by the National and Local Emergency Commissions.
- Members of these are representatives from the
different state agencies, local authorities, and private organizations
with responsibilities in the community.
- If scarcity of water affects sterilization
of medical and non-medical equipment, water from the emergency
storage of ENACAL is used.
- Where ENACAL does not have offices, it is the
mayor’s responsibility to supply water to the population.
- Health centers have post-emergency services
that include chlorination of water systems, fumigation of disease
vectors, and counseling to help with post disaster depression.
- Some municipalities find it necessary to have
a municipal well, since post emergency action is prioritized and
they are often at the end of the line.
- When irrigation is necessary, the water is
taken from the rivers rather than wells.
- Some municipalities have an emergency plan
for both drought and flooding.
- For those sites closer to the larger cities,
water may be trucked in from their sources during times of extreme
- If flooding contaminates the water source,
ENACAL has cleaning teams and a department to monitor contamination
levels and make the necessary adjustments in treatment.
- In those places where communities normally
get their water from small streams and these streams are contaminated,
EBAIS brings them water and uses that opportunity to teach about
not throwing garbage, dead animals, etc. into the water.
- In places where the water source is a spring,
AA fences it in and plants the surrounding area with trees.
- When flooding affects the water source, a citizen
network diverts or pumps excess water away from the source.
- Well water is either filtered or disinfected
- Wells are dug far from any source of contamination.
- Deforestation is prohibited in areas where
there is a water source.
- SILAIS gives educational talks on saving and
storing potable water, and chlorinating wells.
- During a drought, SILAIS provides water to
health centers and hospitals.
- In the more arid areas, water is collected
in barrels and cisterns as early as possible during the rainy
- Most industries in these municipalities have
their own source of water and a large capacity for storage.
- The non-governmental organizations active in
these municipalities work with soil conservation practices and
reforestation of the deforested watersheds.
For the most part, this zone is made up of swamps
and agricultural lands in Costa Rica and low-lying forests and swamps
in Nicaragua in a half-moon shaped strip along the Caribbean coast.
Its northwestern edge has become an agriculture frontier as landless
peasants search for a place to farm. Its southwestern edge has already
been utilized for banana plantations and ranching. By far the largest
part of this coastal zone, however, is made up of a bi-national
complex of protected areas (biological reserves and corridors, wildlife
refuges, forest reserves and national parks) called “Sí-a-Paz.”
At something close to 4,000 Km², these protected areas represent
a significant portion of the SJRB (Map
There are five or six small villages along the
coast that date from the 1850’s, and a dozen or so centers between
the mountains and the lowlands in Costa Rica. These developed even
earlier as large banana and cocoa plantations, which later were
the object of both directed and undirected colonization schemes.
Apart from these centers, some of which are rapidly growing, the
population tends to be lightly scattered along the river, in logging
camps and cattle ranches.
Poverty levels in the occupied areas are high.
Potable water service does not seem to be able to match population
growth, since efforts to supply and adequately administer potable
water in many of the population centers are falling behind demand.
Population centers located on the edge of the
mountains receive muddy water. This is because the high-energy stream
carries more sediment, as well as road construction and landslide
materials. Flood threat is very high because of the lack of elevation,
storm surges, high water tables, and very high annual rainfall of
between 3,000 mm to 4,000 mm inland and up to 6,000 mm along the
coast. Temperatures are high. Hurricane threat is moderate to very
high; the threat of drought is low. Except for the larger population
centers that receive water from AA, the remaining cantons have water
associations or committees that AA regularly advises.
IV Montane Wet (Cordillera headwaters)
- Hospitals located inland can treat many
patients at a time but most have no organized plan to deal with
water problems caused by flooding. Those that do have a plan also
coordinate with the National Commission on Emergencies, AA and
- AA is responsible for protection of potable
water sources; it coordinates with MINAE in the protection of
forests surrounding these sources.
- Emergency commissions are generally made
up of representatives from the fire department, Red Cross, Rural
Guard, the local hospital and the municipality.
- Environmental NGOs support work of reforestation
and forest conservation to protect water sources.
- Communities have lined, raised, and covered
their water sources to protect them from contamination.
- NGOs that manage land calculate the “environmental
value” of letting forests protect the water resource and are paid
this amount which then allows them to give land and water management
advice to other landowners in the area.
This zone stretches along the highlands of Costa
Rica from the Cordillera de Guanacaste in the west, through the
Cordillera de Tilaran and then to the Cordillera Central before
dropping off to the Caribbean Coast. A series of volcanoes, four
of which are over 2000 meters and one of which peaks at almost 3500
meters, marks the southern border of the SJRB. It is a zone of high
precipitation (between 3,000 mm and 5,000 mm annually). Because
of the altitude and seasonal clouding, the relatively cool temperatures
can drop to 10ºC. Most of the area is classified as wet to very
wet pre-montane or montane forest. Many of the tributaries of the
San Juan River form here and supply water to operate industries,
for hydroelectric energy, and groundwater recharge for high quality
potable water. While the southern limit of this zone (and therefore
the southern limit of the SJRB) crosses through at least 15 protected
areas that are administered by MINAE (Map
14), AA, the municipalities,
and the local communities are the primary actors that have direct
responsibilities in the management and operation of urban and rural
Potable water sources and quality vary. Human
populations in the cantons to the west and east get their potable
water from springs and rivers; those in the center from wells or
a combination of rivers, springs and wells; and, further to the
east, potable water of poor quality is taken from rivers and shallow
Hurricane threat is moderate in the extreme northwest
of the zone and low to moderate elsewhere. However, landslides,
mudslides and rivers overflowing their banks can be caused by tropical
disturbances even if somewhat distant, which is worsened by the
increased construction within the flood plains. When water logged,
the steeper soils can fail, destroy water distribution systems,
and fill wells and ponds with sediment. Further downstream, flooding
and water logging often destroy crops.
- Because of the volume
and quality of water available in this zone, many organizations
have been charged, in one way or another, with the care and management
of its sources as well as with its distribution and storage.6
Most do so in coordination with AA, although in the larger cities
water may be administered by the municipality.
- Management and protection of water in the zone fall to many
different groups including water committees, development committees,
communities, students, and non-governmental organizations.
- Classes are given at the health centers on
the management of black and gray water and on how to use untreated
water in those places where only bottled water is recommended
- Classes are also held on how to protect potable
water sources and emphasize that trash, garbage and dead animals
should not be thrown into the river.
- Classes also include information on how to
locate wells and other water sources relative to the location
of latrines and corrals.
- Health personnel monitor water quality in coordination
with other organizations such as the Technical Institute, AA,
- In other parts of this zone, water associations,
water committees, or other institutions take on these tasks.
- There is coordination, with respect to protection
and administration of water, between the business community and
- There is coordination between community water
committees and AA.
- Some of the cantons have an emergency plan for flooding as well
as an emergency committee made up of representatives from the
Ministry of Health, Red Cross, the municipality, fire department,
education centers and members of civil society.
- A canton agricultural center has developed
an education program on land use and how to avoid contamination
of rivers and streams with pesticides, fertilizers, and crop residue.
- Farmers and ranchers, together with
the community in general, have taken it upon themselves to clean
the riverbanks and valleys and to maintain riparian vegetation.
- Some communities have planted crops such
as manioc, bananas and beans that can better withstand heavy rains.
- If allowed, IDA lands can be administered
by a municipality or community as a forest reserve to protect
their water sources.
5 -Often referred to as Lake Cocibolca.
6 - MAG, MINAE, IDA, ICE, SENARA, AA, the
canton municipalities, and public/private energy producers, among