As I live in France I've never heard of your water, but tench are tench.... I agree that fishing the close margin can be very effective. I've actually seen shoals of tench feeding right on the marginal shelves of our lakes.
A couple of years back, while sorting a tangle on my reel, I'd left my plastic corn bait it the edge, inches from the bank. Before I could finish a tench had taken the bait right at my feet.
There's loads of info in the above posts, which will certainly see you catch tench. I guess you'll have to adapt the advise to your type of fishing. Personally I like to target big tench in a traditional specimen hunters approach.
I come at things from a carp angling point of view as in the past, while carping, I have often been pestered by tench using boilies.
These days though, I target big tench using scaled down carp tactics. They love hemp so I often spod out a bed of bait to keep them in the area.
Probably the most attractive groundbaits out there now are halibut pellet based ones. I make a mix of ground up mixed pellets, some crushed up boilies, a few handfuls of whole 2mm betaine pellets and some halibut oil... you can add some hemp and sweet corn if you like. Just add some hot warter and this makes a great, fairly heavy, sticky ground bait that is deadly for tench, carp (and barbel on the rivers).
For tench my preferred technique is a couple of method feeders. ESP have just brought out some brilliant flat Mega feeders with a mould for getting a perfect feederful each time.
I vary the hookbaits, but generally use, Prologic plastic corn (very realistic); a small boilie, a fluro pop up or a piece of Frolic dog biscuit in a bait band. Hooklinks need to be short 4 or 5 inches tops. The presentation is spot on and has seen me bank numerous tench to over 8lb.
Another good tactic over a bed of hemp is a Drennan maggot feeder with a couple of artificial maggots threaded on a hair.
With all these feeder techniques the essential is to keep the bait trickling in, by casting regularly. I start off every ten or 15 mins for the first hour or so then every hour or after a fish.
cheers
Gareth