Post by murrayc on Jun 10, 2019 6:47:50 GMT
A few weeks ago at the Allotment Holders meeting a number of us were all in agreement on how dry a spring it had been so far, and how detrimental that was to growing. Since then we've had another little hot - and dry - spell and now a week of rain, just when we were all getting on top of the weeds! Certainly we're relieved of daily watering chores for a few days, but what is the true state of affairs and for how long? When will we start seeing those news stories showing parched reservoirs?
I looked at Southern Water's website www.southernwater.co.uk/water-resources to try to get some understanding of the facts. Their methodology for jow near or far away from drought we are is based on the relative amounts of Rainfall, Groundwater levels, and Reservoir levels. 70% is taken from groundwater aquifers, pumped up to the surface; 23% from rivers, including a fairly large proportion of greywater that has been cleaned and pumped back into the rivers; and only 7% from reservoirs.
Groundwater trends for the areas closest to us show a steady rise from last summer through this winter away from drought conditions, which is the normal pattern, but quite a dip in recent months. Rainfall tells the same story: actual rainfall in April as 28 mm, but the historical average for this month is 52.8 mm, and only February this year has been above the long-term average. Finally reservoirs: Bewl Water is our main source for Mid Sussex and it is currently at 91% capacity. The trend shows that it has been fully than winter this usual and is no about on a par with its 13 year average. That sounds fine, but what is less encouraging is that the average is only a few percentage points above the minimum level and that the trend for all of these is to converge quite closely at midsummer. In other words if we don't have significant and prolonged rain to fill that reservoir soon we shall be seeing those pictures of exposed land.
The overall picture that shows itself to me is that water supply is managed quite closely at just above minimal levels and that any prolonged period of dry weather sends it tipping into crisis. Groundwater levels sound most encouraging but longer term as we all know the effects of new building demands and of ageing piping needing constant replacement to avoid leakage are worrying.
Meanwhile I will keep hoeing up the weeds - at least they come up nice and easy in the wet - and will not be too ungrateful for some damper days in flaming June.