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Rivers |
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How
the rivers flow Two
rivers (the Ignon (for 8,5 km) and the Tille (for 3,5 km)) run through
the area covered by the commune. It’s the Ignon, and not the Tille,
which runs through the centre of the town. Along its route are 7 sluice gates
(two of which belong to the commune), 7 overflows (2 ot which belong to
the commune) and 6 reaches, two of which are called “false rivers”. On its
banks are 5 covered “lavoirs” (washing places), 2 of
which belong to the commune. Access
is provided by both publically and privately owned bridges. There are
35 of these, 22 of them footbridges. Two pumping stations along the river
serve the communes of Is-sur-Tille and Chaignay. A
purification plant treats the water used in Is-sur-Tille and Marcilly.
Among other objectives, two river associations exist to maintain the
ecosystem and to make sure the water flows freely. |
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State
of cleanliness
According
to
the surveys, the rivers
are generally
clean but at certain times
are
still not
good enough to support aquatic life or for drinking
water
.(due
to nitrates,
phosphates, weed-killers,
heavy metals, hydrocarbons…)
Improvements
currently
being made, as well as those planned by the council, will
reduce these various pollutants
through careful
monitoring and adjusting rainfall levels across the network of
waterways,
and
by
purifying the water.
There will be decantation ponds for the most built-up areas and
monitoring and cleaning up of the sewage discharged
into the river via natural outlets. Fish The level of fish life in the commune's rivers (classified as in the top category) is good but erratic. Trout, minnows ahd chub are the best indicators of clean water. The local angling society, La Saumonnée, is trying to reintroduce the common grayling, a member of the salmon family. In hot weather, dace and lamprey can be found. Pike and perch, common predators, are also present. As far as above-water life is concerned, there are mallards, coots, grey herons, kingfishers, divers and slowworms. Coypus, not indigenous to the area, have colonised the river banks. |
Maintenance Upkeep of the river is being organised. The river associations, assisted by the national and local angling societies, have the overview. Every three years they prune the trees and decide what species to keep. They cut the trees which overhang the water and may uproot. They remove obstructions of branches or tree trunks which prevent the river from flowing freely. Light cleaning or reinforcing of the banks have to be authorised. They are allowed in any emergency or when there is a risk, e.g. flooding. For minor maintenance the commune has created an environmental youth post to make sure that the grass on the little islands is cut regularly and to clear litter such as plastic bottles and branches. It is alos this person's job to clear away earthfalls and do a bit of light pruning. This job is soon to include working the sluice gates (exactly how is being studied at the moment), reinstalling mini waterfalls and planting trees, shrubs and river plants to make sure the river banks are looked after. Water study A full water study of the Ignon, carried out at the council's request in 1998 and containing further, more technical information, is available at the town hall for anyone who wishes to look at it. |
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General study A general study for the Tille-Ignon and East Dijon area basins was ordered by the Conseil Général (local authority for the Côte-d'Or département). It was carried out with the technical help from the river associations and other interested parties. The aim of the research was to have an overall view of how the rivers flow in order to be able to solve existing problems whilst still taking into account economic, social, fish-related and environmental concerns. This latter includes floods, maintaining a minimum water level, irrigation, pollution, countryside management, leisure, tourism and fishing. Translated by Jill Amey
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