Rainfall
The flow in the River Ver is dependent on rainfall to recharge the aquifer, from which water is pumped to supply the needs of the district (see Aquifer page). Recharge largely happens in the winter and early spring; any rainfall during the summer has little effect as surface water evaporates and is used up by growing vegetation. Although after heavy rains, at any time of year, the run-off can cause short-term improvement in flow, it takes many weeks for any effect to be measured in aquifer levels or to have any long-term effect on the river.
It is therefore important for the Ver Valley Society to monitor rainfall figures regularly throughout the year and we do this with the help of Rothampstead Research Station (see tables below). 2008 was the wettest year since 2000. In 2009 rainfall was nearly 10% above average and as the Bow Bridge Pumping Station (see aquifer notes) was shut down until August good flows were recorded in the first half of that year and the aquifer came back to average values. Subsequent rainfall in 2009 and 2010 generally fell below average but flows remained moderate. However poor winter rains and most of 2011 mean the river was exceptionally low by the end of 2011.
See rainfall figures below.
Rainfall 2011
| Month 2011 |
Actual rainfall (2010) Millimetres |
Average Rainfall in Millimetres |
+/- mm Average |
Percent Average |
| January |
84.6 |
70.0 |
14.6 |
120.9% |
| February |
56.8 |
50.1 |
6.7 |
113.3% |
| March |
10.0 |
50.8 |
-40.8 |
19.7% |
| April |
5.2 |
55.1 |
-49.9 |
9.4% |
| May |
23.6 |
54.7 |
-31.1 |
43.2% |
| June |
83.0 |
53.3 |
29.7 |
155.8% |
| July |
44.6 |
49.9 |
-5.3 |
89.4% |
| August |
81.2 |
63.7 |
17.5 |
127.4% |
| September |
38.4 |
57.6 |
-19.2 |
66.6% |
| October |
25.2 |
81.7 |
-56.5 |
30.9% |
| November |
36.4 |
76.6 |
-40.2 |
47.5% |
| December |
82.4 |
69.5 |
12.9 |
118.5% |
| |
|
|
|
|
| TOTALS |
571.4 |
732.9 |
-161.5 |
78.0% |
Rainfall 2010
| Month 2010 |
Actual rainfall (2010) Millimetres |
Average Rainfall in Millimetres |
+/- mm Average |
Percent Average |
| January |
47.3 |
69.7 |
-22.4 |
67.9% |
| February |
77.2 |
48.8 |
28.4 |
158.2% |
| March |
45.2 |
53.9 |
-8.7 |
83.8% |
| April |
18.7 |
53.4 |
-34.7 |
35.0% |
| May |
38.4 |
49.7 |
-11.3 |
77.3% |
| June |
23.5 |
60.2 |
-36.7 |
39.0% |
| July |
31.6 |
42.1 |
-10.5 |
75.1% |
| August |
127.6 |
53.5 |
74.1 |
238.3% |
| September |
59.7 |
61.0 |
-1.3 |
97.9% |
| October |
84.9 |
74.7 |
10.2 |
113.7% |
| November |
54.9 |
66.3 |
-11.4 |
82.8% |
| December |
35.3 |
70.1 |
-34.8 |
50.4% |
|
|
|
|
|
| TOTALS |
644.3 |
703.4 |
-59.1 |
91.6% |
Rainfall 2009
| Month 2009 |
Actual rainfall (2009) Millimetres |
Average Rainfall in Millimetres |
+/- mm Average |
Percent Average |
| January |
70.4 |
69.7 |
0.7 |
101.0% |
| February |
73.9 |
48.8 |
25.1 |
151.4% |
| March |
37.3 |
53.9 |
-16.6 |
69.2% |
| April |
46.7 |
53.5 |
-6.8 |
87.3% |
| May |
24.8 |
49.7 |
-24.9 |
49.9% |
| June |
68.1 |
60.2 |
7.9 |
113.1% |
| July |
73.3 |
42.1 |
31.2 |
174.1% |
| August |
63.4 |
53.7 |
9.7 |
118.1% |
| September |
15.9 |
61.0 |
-45.1 |
26.1% |
| October |
39.1 |
74.7 |
-35.6 |
52.4% |
| November |
146.1 |
66.2 |
79.9 |
220.6% |
| December |
105.2 |
70.1 |
35.1 |
150.0% |
|
|
|
|
|
| TOTALS |
764.2 |
703.6 |
60.6 |
108.6% |
Rainfall 2008
| Month 2008 |
Actual rainfall (2008) Millimetres |
Average Rainfall in Millimetres |
+/- mm Average |
Percent Average |
| January |
103.20 |
69.70 |
33.50 |
148.1% |
| February |
21.90 |
48.80 |
-26.90 |
44.9% |
| March |
108.50 |
53.90 |
54.60 |
201.3% |
| April |
53.50 |
53.50 |
0.00 |
100.0% |
| May |
87.00 |
49.70 |
37.30 |
175.1% |
| June |
35.30 |
60.20 |
-24.90 |
58.6% |
| July |
90.3 |
42.00 |
48.30 |
215.0% |
| August |
107.8 |
53.70 |
54.10 |
200.7% |
| September |
66.2 |
61.00 |
5.20 |
108.5% |
| October |
74.3 |
74.7 |
-0.40 |
99.5% |
| November |
91.1 |
66.2 |
24.90 |
137.6% |
| December |
42.0 |
70.1 |
-28.10 |
59.9% |
|
|
|
|
|
| TOTALS |
881.10 |
703.50 |
177.60 |
125.2% |
Rainfall 2007
| Month 2007 |
Actual rainfall (2007) Millimetres |
Average Rainfall in Millimetres |
+/- mm Average |
Percent Average |
| January |
91.60 |
69.70 |
21.90 |
131.4% |
| February |
97.44 |
48.60 |
48.84 |
200.5% |
| March |
57.60 |
53.90 |
3.70 |
106.9% |
| April |
2.80 |
53.50 |
-50.70 |
5.2% |
| May |
135.80 |
49.70 |
86.10 |
273.2% |
| June |
72.40 |
60.20 |
12.20 |
120.3% |
| July |
86.8 |
44.60 |
42.20 |
194.6% |
| August |
64.6 |
53.90 |
10.70 |
119.9% |
| September |
29.2 |
61.00 |
-31.80 |
47.9% |
| October |
57.1 |
74.7 |
-17.60 |
76.4% |
| November |
80.0 |
66.2 |
13.80 |
120.8% |
| December |
67.1 |
70.1 |
-3.00 |
95.7% |
|
|
|
|
|
| TOTALS |
842.44 |
706.10 |
136.34 |
119.3% |
Rainfall 2006
| Month 2006 |
Actual Rainfall (2006) Millimetres |
Average Rainfall Millimetres |
+/- mm Average |
Percent Average |
| January |
29.20 |
69.70 |
-40.50 |
41.9% |
| February |
41.40 |
48.80 |
-7.40 |
84.8% |
| March |
49.50 |
53.90 |
-4.40 |
91.8% |
| April |
51.00 |
53.50 |
-2.50 |
95.3% |
| May |
89.00 |
49.70 |
39.30 |
179.1% |
| June |
15.00 |
60.20 |
-45.20 |
24.9% |
| July |
35.60 |
42.10 |
-6.50 |
84.6% |
| August |
110.00 |
53.70 |
56.30 |
204.8% |
| September |
54.20 |
61.00 |
-6.80 |
88.9% |
| October |
105.00 |
74.70 |
30.30 |
140.6% |
| November |
104.40 |
66.20 |
38.20 |
157.7% |
| December |
95.00 |
74.10 |
20.90 |
128.2% |
| |
|
|
|
|
| TOTALS |
779.30 |
707.60 |
71.70 |
110.1% |
Rainfall 2005
| Month 2005 |
Actual rainfall (2005) Millimetres |
Average Rainfall in Millimetres |
+/- mm Average |
Percent Average |
| January |
33.8 |
69.7 |
-35.9 |
48.5% |
| February |
36.2 |
48.8 |
-12.6 |
74.2% |
| March |
43.2 |
53.4 |
-10.2 |
80.9% |
| April |
65.6 |
53.5 |
12.1 |
122.6% |
| May |
44.4 |
49.7 |
-5.3 |
89.3% |
| June |
44.0 |
60.2 |
-16.2 |
73.1% |
| July |
39.0 |
42.1 |
-3.1 |
92.6% |
| August |
58.6 |
53.7 |
4.9 |
109.1% |
| September |
65.0 |
61.0 |
4.0 |
106.6% |
| October |
88.4 |
74.7 |
13.7 |
118.3% |
| November |
53.8 |
66.8 |
-13.0 |
80.5% |
| December |
53.0 |
74.5 |
-21.5 |
71.1% |
| |
|
|
|
|
| TOTALS |
625.0 |
708.1 |
-83.1 |
88.3% |
|
