"Ox-bow Fry Refuges".
What one quickly comes to learn when trying to unravel the problems that face our rivers are that many if not all have common factors. When we came to look at the impact of large flood events on the salmon redds it became obvious that they not only impact on the salmon but much of the ecology of the Avon. When the salmonid ova and fry are still within the gravel and the flow is confined within the banks of the channel the vital gravel shoals are at risk of scouring, thus destroying salmonid year classes. This same high velocity flow potentially impacts upon invertebrate and juvenile cyprinid populations by flushing them through the system when they are unable to swim against the current or gain access to slacks and back channels. On the Avon the number of weirs, hatches and trout farms mean that once flushed over such a barrier they are lost to that section. Immediately south of Salisbury where the five rivers meet and at Christchurch at the bottom of the river some beats benefit from this flushing giving rise to increased numbers of some species. The Avon has a one way system which potentially moves year classes or entire populations downstream through the system. These same structures prove impassable barriers to the subsequent upstream adult spawning migrations preventing populations re-establishing themselves. The decline of the water meadow system combined with the removal of obstructions and the canalisation of much of the river for flood defence purposes in previous decades has created a harsh environment for many species.
The lack of suitable refuge habitat combined with the increased frequency of major flood events, (there has been three one hundred year probability events in the previous two decades), is believed to have contributed to missing cyprinid year classes particularly roach.
To evaluate just what impact this flood effect is having, the trust have embarked on a project to provide sanctuary areas of slack water by clearing out two silted and blocked ox-bows on the Somerley Estate.
The project is specifically designed to benefit the indigenous species of the River Avon SSSI and the Avon Valley SSSI/SAC. Its sole purpose is that of habitat improvement.
If the project proves that there is a benefit in providing refuges it is hoped to use the scheme as a model for export throughout the region. We are designing a monitoring programme with Sparsholt College to evaluate and record the value of these bays. Dependent on the outcome we will decide the trust policy related to future commitment to this work.
We envisage this will be a collaborative project with riparian support from Somerley Estate, Christchurch Angling Club, as the tenants. and Sparsholt College, as previously mentioned, will be monitoring the project.
We have had considerable help and advice from the Environment Agency and English Nature who have been very positive. We are now at the consent stage with the drawings and paperwork with the agency hopefully for approval.
We believe this to be a very exciting initiative that has enormous potential not only for the ecology of the valley but also as an example of positive action designed to meet raised concerns.
Having completed the east side or left bank element (Coomer), the larger oxbow below Park Pool is underway, the fallen spiny oak has been left as a natural bridge.
The photos below show the construction of an otter holt as part of the oxbow habitat improvement scheme. Perhaps a little controversial in light of the number of fish kills to be found in the valley but as the predator at the top of the food chain their presences is vitally important to any ecological balance. In a healthy, self sustaining ecology there is room for all species to live in harmony, it is only when imbalances are present that problems arrive. If the fish that anglers seek, that in turn are the base of the economic survival of the river, are suffering population fluctuations and otters predate threatened stock conflicts of interests arise. Otters enjoy protection under the law and rightly so but where that protection detrimentally impacts on the livelihood of individuals a mechanism for compensation should perhaps be available to ensure loss of income and associated hardships do not arise. We are currently looking at the problems associated with establishing a scheme such as that proven to work in the states where Puma and wolves are being given protection that gives rise to similar conflicts of interest on a proportionally larger scale; I suppose we should be grateful otters don't eat cows but if you consider a large carp or barbel has a similar economic value what's the difference?
The stages of construction showing the final waterlevel entrance necessary to prevent it filling up with badgers as the park is, in local terminology, "cooty with them." It is not unusual to see seven or eight badgers at a time out rumaging about on the park in the evenings and any suitable housing is quickly occupied.
Trust Vice President, Hugh Miles, filming the conservation work that is ongoing in the Avon Valley. Hugh is putting together a record of the projects as we endeavour to understand and assist in the recovery of the rivers; to take the positive message to a wider audience. I must say it is a long time since I have felt such a "feel good" factor within the angling community and in Hugh we are extremely fortunate in having an unparalleled talent available to spread the word.
Hugh recording phase one of the oxbow project in all its raw, nakedness. Within a twelve month we will see the transformation as Mother Nature cloaks herself in green and the creatures of the valley find the new areas of water and reeds that will be available to them.