LATE WINTER RAMBLINGS
Right, having had a few minor problems getting our blog to work the way it used to I have been guilty of just using Facebook to keep people up to date. Now that I have the blog back and intend to keep everyone up to date with the current state of play please excuse me if I’m covering some areas of old ground.
There appears to have been a major change with the lake this winter and I have been puzzled, very pleased and excited but puzzled nevertheless, so here’s a bit more detail in what work has been done.
A lot of you will know that the big weeping willow died last summer. That has been cut back but left as major stumps with our plan to allow wisteria and clematis plants to ramble over it. At the same time we took down the two big conifers which were on the garden slope of the dam wall and intend to allow flowering climbers to ramble over these also. We have also removed some other trees from the garden but these were solely to reduce the leaves in the swimming pool so doesn’t really affect the angling side of things. However, one small but very exciting discovery was that we found the kingfisher nest burrow and it is well above the highest water level that we’ve ever had.
Before Christmas, and before the water level rose, I trimmed off as many of the old reed stems around the lake margins, as possible so that this spring would see just the fresh green growth and not the dead stems. In truth it also reduces the rats hiding places so they are easier prey for the kites and buzzards and also that the coots have less nesting material. Those cut stems are now beginning to float off and I have spent the last week shepherding them over the spillway and into the garden stream. Now that leads nicely to the most exciting bit.
As the water level slowly rose I became aware that the water was extremely clear compared with all of the previous seventeen years that I have owned the place. Now I expected it to colour up as the water flow continued but it hasn’t and the lake is now completely full, trickling over the spillway, and still clearer than ever before. I have lots of theories about why this may have happened but they are all guesses and will probably not be able to be proven one way or the other.
The theories in my head refer to two changes that we’ve made and they probably both contribute to the clarity. The first is the aeration system that we installed a few years ago. The “air lift” effect that is caused by the constant stream of micro bubbles rising to the surface creates a major vortex around each diffuser head and this vortex drags in the soft silt which, in turn gets lifted to the surface and turned over in the oxygen rich surface area. We do know that oxygenating the silt encourages the bacteria to begin eating into it and thereby reducing the volume of silt so I believe that the oxygenated silt is sinking back to the lake bed and beginning this process. The second change that we made, last March, was to spread calcium carbonate across the lake before the season began. This is commonly called “liming” but I decided to use the calcium carbonate that is produced as a cattle feed supplement rather than the basic “chalk” which is recommended at one tonne per acre which sounds far too much for my liking. I will just add here that I was worried that the ph of the calcium carbonate would effect the ph of my lake, which sits at 8.2, until a fellow fishery owner pointed out the obvious fact, very obvious, but a fact that had eluded me, that the calcium carbonate reading was the same as my lake so it wouldn’t change our ph at all. Either or both, and probably both, of these changes may be the factor that is making the lake water clearer but here comes another part to this jigsaw.
As I mentioned above, I have recently been feeding the floating reed stems over the spillway but I was also aware that there were still more cut stems that were hung up on the banks and need a bit or persuasion to get them free floating. To achieve this I again donned my chest waders and slid into the cold water, lawn rake in hand, at Billy no Mates. By walking slowly along the lake margin I could pull the cut stems out past me and off out into the lake where the breeze would blow them up towards the spillway. It wasn’t until I had walked, and worked, from the marsh filter fence to Snag Bay that it dawned on me, I hadn’t yet sunk into any silt? The lake bed is firm. As this realization crept up on me I decided to wade further out in order to check other areas. Up to this point I had been at about waist depth so I worked my way further out until I was at the limit of my chesties. The deepest part of soft lake bed that I could find was not even ankle deep in silt/clay and even then I could feel the solid lake bed beneath it as I waded through it. In the light of these discoveries it is my intention to leave the aerators running 24/7 and to also make another application of calcium carbonate this year.
As an indication of the changes I remember, back in the early years and probably 2005/6 ‘ish, having to wade out to free a carp that had gone around the third lilies. I could just about get there in chesties and lifted the line free but as I lowered my arm back into the water my fingers were touching the top of the silt. This means that the silt, although very liquid at that time, was above knee deep with barely a couple of feet of water above it, now it is less than ankle deep so the fish have a far, far better environment in which to live and grow.
I’m probably going to be proven wrong but I believe that the reduction in silt volume also leads to less suspended, polarized clay particles making the water turbid and if this is the case then we may keep the clearer water and this may also see our carp develop darker colours this year.
Let’s hope I’ve got it right.