Most farms have a pond. Usually small and located near the farmyard, they were traditionally used to provide a home for ducks and a handy source of water for the animals. The advent of mains-supplied water meant that these ponds were no longer essential. However, there is one type of farm pond that is on the increase – the irrigation or storage pond.
There are several reasons for this growth, the main one being farmers’ reluctance to pay for anything they can get for free. Water privatization has certainly made them aware of the cost of this valuable commodity and the prospect of metering is alarming many.
Recent droughts, water shortages and long, hot summers have also been responsible for an increase in the construction of agricultural reservoirs. The benefit of saving rainfall has not been lost on farmers and in many parts of the country this has given anglers an unexpected bonus.
Spuds-u-water a lot
John takes us to a typical irrigation pond in Norfolk – most of its features can be found on storage lakes elsewhere. Roughly 1 ½ acres in size, the lake was dug about eight years ago to provide water for the potatoes and fruit growing in the fields nearby. Apart from rainfall and water draining off these surrounding fields, the lake is fed by a small stream.
This is the outflow from another, much older, storage lake on a different part of the farm. Spring and early summer is the crucial time for spud cultivation, and large amounts of water are pumped from the lake to the fields. This results in a large drop in the lake’s water level and thus alters the location and feeding habits of its fish.
Top to bottom
The lake is roughly 100m (110yd) long and 60m (65yd) across at the dam end. There is a large tree-covered island on one side of the lake, but a huge bed of Norfolk reed has filled in the space between it and the bank. The feeder stream flows into the top end of the lake. Next to this is a small spur containing the draw-off pipes connected to the pumphouse standing on the bank above.
When the lake is full there is about 1.2m (4ft) of water at the top end and this gradually increases to 2.4m (8ft) at the deepest part, which is by the dam. However, for most of the lake’s length this deep water is only found down the 10m (11yd) wide central channel. The rest of the lake consists of a shallow (60cm/2ft) shelf.
The lake supports a healthy amount of weed; the banks are fringed with Norfolk reed, and they give way to vast rafts of amphibious bistort that cover the shallow shelf. Lining the central channel are clumps of Canadian pondweed.
Apart from a group of mirror carp introduced recently, the lake has stocked itself. It contains about 60 large crucian carp, some approaching record weight, according to John. There are also roach, rudd, pike, eels and a few tench and bream – all species common in irrigation ponds.
Most of its inhabitants have undoubtedly been washed down the feeder stream in times of flood, while the others, possibly, have entered via the proverbial ‘heron’s leg7 method. There are large amounts of roach, rudd and pike fry in the water, but no young crucian or mirror carp.
The reason for this is one common to waters of this type. The roach, rudd and pike spawn in the cold water of early spring when the lake is full of winter rainwater. Their eggs, laid in weed on the shallow shelf, have hatched by the time the water warms up. The spring sunshine dries out the crop fields which are then watered from the lake. The level of the lake drops, exposing and drying out the shelf, which means there are no weedy margins for late-breeding carp to lay their eggs on — or if they have spawned, their eggs are exposed and die.
All dried out
During the spring and summer the level of the lake rises and falls depending on the weather and the farmer’s needs. During a hot summer the shelf is exposed for a lot of the time and the weed on it withers. Ducks and geese eat this and at the same time ‘fertilize’ the baked mud, which has now become host to land insects.
When it rains and the level rises, fish move in to feast on these new sources of food – anglers can have a bonanza when this happens. The water also revives the hardy, deep-rooted lilies that shelter the carp, crucians and rudd.
Up and down
With the water level low, the fish have no alternative but to move into the deep water of the central channel. Only the overhanging trees and bushes around the island can offer any shelter near the surface.
Underwater the fish tend to stick closely to the relative sanctuary of the clumps of pondweed.
Because the water level in the lake is constantly changing for much of the year, the fish tend to become very versatile, both in the types of food they eat and the time of day they eat it. Locating fish in an environment that can alter suddenly may be a problem for the angler, but simple observation is usually the solution – if you can see them, then that’s where they are.