1. Savannah Groundwater Province
Threats and Challenges
Rudolph S. Williams Jr.
Coastal Aquifer Management in the Caribbean Workshop
December 2011
Trinidad & Tobago

2. The Request/Concern
Question: Considering the demand for water supplies for the Villages, Tourism developments, currently operating, under construction, approved and awaiting funding, can the Savannah Groundwater Province suffice. Quick Answer: I do not know. That was not the desired response Please provide some indication if the concern is valid.

3. Belize’s Groundwater Provinces
The Coastal Plain and Shelf Province - weathered and fractured Miocene-Pleistocene limestone and marls overlain with clay and marl alluvial deposits
The Coastal Plain and Cayes Province - quaternary alluvial deposits unconsolidated beach and coral sand overlying weathered marine carbonate and coral reef deposits.
The Vaca Plateau Province Fractured and karstic Triassic superior limestone and dolomites.
The Campur Province - Primarily quaternary alluvial deposits and Miocene-Pleistocene sedimentary materials overlying porous and fractured Paleocene-Eocene limestone formations.
The Maya Mountains Province Metamorphosed late Carboniferous-Permian volcanic material with abundant dense granitic intrusions.
The Toledo Province generally tertiary limestone overlain with tertiary inferior sedimentary deposits except in the extreme southeastern region where it is overlain with quaternary alluvial deposits.

4. 7. Savannah Groundwater Province
Geology: Mostly Eocene Claystones, and Calcareous sandstones overlain by quaternary alluvium. Area : 1,547,750,713 m2 25 Communities Population 21,941 (2010 census) Doubled since Rudimentary Water Systems 21 Operating Tourists Facilities 9 Tourist facilities under Construction 4 Approved Tourist facilities awaiting funding 1 International Airport under construction 12 Aquaculture Farms& Processing facilities Citrus Farms (approx 100 km2) Banana Farms (approx 90km2) 33 Production wells 9 Abandoned Wells (Identified) Investment value of tourism developments in this province exceed $US500 million

5. SAVANNAH GROUNDWATER PROVINCE STRATIGRAPHY - CONCEPTUAL
Based on 4 well logs - well logs difficult to obtain or do not have sufficient details. Lower eastern extent of the strata corroborated (near Ara Macao). Elsewhere not corroborated.

6. Savannah Groundwater Province Recharge Area
Jean Cornec delineated the boundaries of the province (2m and 100 m contours), however, no mapping of the recharge areas were done.
The width of the recharge was mapped to be above the western extent of the phreatic aquifers 60 m contour and the western extent of the province.
Estimated area:
417,850, m2

7. Calculating Recharge
Recharge (R)
The water-budget method was used 
R = P - Eto - Ro – S
where:
R = ground-water recharge (m3)
P = precipitation (m,m3)
Ro = overland runoff (m3)
Eto = evapotranspiration (m3)
S = Aquifer storage (m3) 
if is abstraction is less than or equal to recharge
R = P – Eto – Ro
Rainfall was provided by the NMS and projections were calculated using INSMET’s PRECIS model run outputs
National Resources Conservation Service’s (NRCS) Curve Number (CN) method was used to calculate Runoff
A fixed percent method was used to account for Evapo-transpiration (15%)

9. Calculating Water Demand
Rudimentary Water Systems
Developments
The annual demand as detailed in the Environmental Impact Assessments for each development project was used to project the development’s demand for the next 40 years. The construction and occupancy schedules were factored into the timing of the water demand. The sum of all developments represented the water demand from the Province.
The average annual water increase in abstraction for each RWS was applied individually to the 2010 abstraction rate to project the abstraction for the next 40 years. The sum of all RWS as then used to project the RWS water demand from the Province.

12. AVERAGE WATER DEMAND
482,076,007 m3

14. QUALIFIED RESPONSE THERE IS NO NEED FOR CONCERN AT THIS TIME
THERE IS THE NEED TO ADDRESS THE WATER DEMAND FOR RWSs
THERE IS THE NEED TO IMPLEMENT WATER DEMAND MANAGEMENT STRATEGIES
THERE IS THE NEED TO RECONSIDER THE TOTAL RELIANCE ON GROUNDWATER
EXPLORE SURFACE WATER OPTIONS TO AUGMENT FUTURE DEMAND

15. CAUTION STATEMENT RECHARGE CALCULATION WATER DEMAND PROJECTIONS
THERE WAS NO FIELD MAPPING OF THE RECHARGE AREA
FIXED PERCENT EVAPOTRANSPIRATION IS NOT BE THE BEST OPTION
WATER DEMAND PROJECTIONS
RWS IS BASED ON HISTORICAL USE – Over Estimate?
THERE ARE LIMITS FOR VILLAGE THE EXPANSIONS

16. THREATS CONTAMINATION Cross contamination
All abandoned wells were not properly decommissioned
All abandoned well were within 500 metres of a production well
7 were used for the disposal of refuse
Cross contamination
Poor well drilling techniques, no sealing of upper aquifers before proceeding to drill to lower aquifer
No well drilling permitting procedure
Anyone can bore a well and abstract water

17. IRRESPONSIBLE DEVELOPMENT
CHANNEL DREDGING TO ACCOMMODATE LARGE SHIPS INCREASE PORT CAPACITY AND IMPROVE OPERATIONS
12 METRES DEEP – DEPTH TO UPPER CLAY LAYER 1500 METRES INLAND WAS 7 METRES. WAS THE CONFINING LAYER COMPROMISED ???

18. Challenges
Despite the unavailability of reliable information recommendations need to be made
Availability of well logs
Difficult to obtain
Poor quality when available
42 Wells, only 4 good logs were available
Statistical Institute reports population data by administrative districts not watershed much less groundwater provinces
No official population projections were available

19. Recommendations Start monitoring groundwater systems now
Next year you will have at least 1 year data to use as guidance
Initiate well drillers training programs
Cross aquifer contamination is difficult, if not impossible to rectify
Ensure that all abandoned wells are properly decommissioned
Contamination of groundwater systems can lead to serious health risks

20. rwillliams@puc.bz Rudolph_williams@hotmail.com
Thank You
Coastal Aquifer Management in the Caribbean