TUESDAY, JUNE 14, 1977
+ IF IT IS DISTRIBUTED IN PROPORTION TO THE MONTHLY AVERAGES, THERE WOULD NORMALLY BE A GRADUAL INCREASE IN STORAGE THROUGHOUT THE SUMMER, SO THAT DECISIONS COULD BE MADE PROGRESSIVELY IN THE LIGHT OF GAINS IN THE RESERVOIRS.
+ IF, HOWEVER, THE RAINFALL DISTRIBUTION WERE TO BE UNFAVOUR- ABLE, AS AT PRESENT, WITH LITTLE RAIN IN THE INITIAL PERIOD OF THE WET SEASON, THE SITUATION WOULD DETERIORATE MORE RAPIDLY AND DEPENDING ON THE AMOUNT OF YIELD FROM THE RAINFALL EARLIER IMPOSITION OF RESTRICTIONS MIGHT BE NECESSARY,+ HE SAID.
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MR. TUCKER SAID IT MIGHT SEEM PARADOXICAL THAT RESTRICTIONS WERE NECESSARY WHEN RAINFALL RECORDED IN MAY AT THE ROYAL OBSERVATORY INDICATED THAT APPARENTLY ENOUGH HAD FALLEN TO STAVE OFF RESTRICTIONS. BUT IN FACT THE OBSERVATORY RECORDS IN MAY HAD NOT BEEN REPRESENTATIVE OF THE RAINFALL OVER THE WATER GATHERING GROUNDS, AS CLEARLY ILLUSTRATED BY EXISTING STORAGE LEVELS.
+AS A RESULT OF THE UNEQUAL DISTRIBUTION WE FOUND OURSELVES IN THE DISAPPOINTING SITUATION OF COLLECTING A YIELD OF ONLY 1,900 MILLION GALLONS DURING THE MONTH OF MAY -- A SUBSTANTIAL AMOUNT BELOW THE FIGURE OF 3,000 TO 4,000 WHICH I HAD INDICATED PREVIOUSLY WOULD BE NECESSARY BEFORE THE END OF MAY IF RESTRICTIONS WERE TO BE AVOIDED,+ HE SAID.
+THIS POOR YIELD WAS DUE, IN PART, TO THE EXTREMELY DRY GROUND CONDITIONS -- THE EARLY RAINS DOING NO MORE THAN PROVIDING PLANT MOISTURE AND RESTORING THE DEFICIT IN GROUND WATER LEVELS.+
MR. TUCKER SAID THE QUANTITY OF WATER IN STORAGE AT THE BEGINNING OF THE WET SEASON NEED NOT BE AS GREAT AS THAT AT THE BEGINNING OF THE DRY SEASON, IF STORAGE IN SUCCESSIVE MONTHS THROUGHOUT THE SUMMER PROGRESSIVELY INCREASED TO COPE WITH BOTH THE SUMMER DEMAND AND TO BUILD UP ADEQUATE RESERVES TO SEE US THROUGH THE WINTER. BUT THIS HAD NOT BEEN THE CASE THIS SUMMER.
+WE ARE THEREFORE CAUGHT BETWEEN TWO STOOLS. ON THE ONE HAND, WE HAVE KNOWLEDGE OF THE RAIN THAT HAS ALREADY FALLEN AND ITS CONTRIBUTION TO STORAGE, AND ON THE OTHER WE HAVE SEASONAL FORECAST OF RAINFALL, THE DISTRIBUTION OF WHICH CANNOT BE ASSESSED WITH ANY DEGREE OF ACCURACY, HE SAID.
IN ASSESSING THE FUTURE DEMAND, THE WATER SUPPLIES DEPARTMENT SIMULATED A SERIES OF SITUATIONS OF VARYING RAINFALL AND ITS ASSOCIATED YIELD, STARTING FROM THE BASE POINT OF THE KNOWN STORAGE AND OTHER FIXED INPUTS SUCH AS CONTRIBUTION FROM THE DESALTER AND WATER FROM CHINA.
THE RAINFALL FIGURES USED WERE GENERATED FROM THE 90 YEARS OF RECORDED RAINFALL AT THE ROYAL OBSERVATORY.
/WITH THESE