Annex 2

(Art. 6, 8, 13 and 47)

Requirements on Water Quality

1 Surface waters

11 General requirements

¹The water quality must be such that:

1. no visible colonies of bacteria, fungi or protozoa and no unnatural proliferation of algae or higher water plants are formed in any waters;
2. fish-spawning grounds are preserved;
3. after application of appropriate treatment, the water complies with requirements of the legislation on foodstuffs;
4. groundwater is not contaminated by infiltration of water;
5. the hygiene requirements for bathing are met at sites where bathing is expressly permitted by the authorities or where a large number of people normally bathe and the authorities do not advise against it;
6. substances that enter waters as a result of human activities do not detrimentally affect the reproduction, development and health of sensitive plants, animals and microorganisms.

²After wastewater has undergone homogeneous mixing with the body of water the mixture must not result in:

1. the formation of mud;
2. any turbidity, discoloration or foam, except in the event of heavy rainfall;
3. any noticeable alteration in the odour of the water in comparison with its natural state;
4. any lack of oxygen or unfavourable pH values.

³The following numerical requirements apply to every water flow after thorough mixing of the wastewater discharged into the receiving waters; a reserve may be made for particular natural conditions such as water discharge from mires, rare high-water peaks or rare low-water events.

12 Additional requirements for watercourses

¹The water quality must be such that:

1. no visible iron sulphide patches form in the channel bed, unless due to particular natural conditions;
2. nitrite and ammonia concentrations do not interfere with the reproduction development and health of sensitive organisms, such as salmonidae.

²The oxygen content on the channel bed must not be adversely affected by:

1. increased oxygen consumption due to an unnatural excess of oxidisable substances;
2. a reduced permeability of the bottom resulting from unnaturally high sedimentation of fine particles (clogging) or artificial sealing.

³The hydrodynamics, morphology and temperature conditions of the water must not be so changed by water withdrawals, water discharges and building activities that its self-purification capacity is reduced or the water quality in the body of water is made insufficient to sustain communities specific to it.

⁴The introduction or the withdrawal of heat must not alter the temperature in a watercourse by more than 3 °C above or below the temperature in its as near natural as possible state, or, in trout water stretches, by more than 1.5 °C; furthermore, the water temperature must not exceed 25C°. These requirements apply after thorough mixing.

⁵The following numerical requirements apply to every water flow after thorough mixing of the wastewater discharged into the receiving waters; a reserve may be made for particular natural conditions such as water discharge from mires, rare high-water peaks or rare low-water events.

13 Additional requirements for standing waters

¹The morphology and functions of the upper layers of sediments which are essential for providing the water quality required to preserve the communities of plants, animals and micro-organisms must not be durably altered by changes made to the terrain (e.g. dredging, movement of excavated material within the expanse of water, levelling or backfilling of banks, reinforcement of banks or creation of dikes).

²The nutrient content should allow at most an average production of biomass; subject to particular natural circumstances.

³For lakes, moreover, the following applies:

1. the regulation of the lake waters, the discharge and extraction of water, the use of water for cooling and for the extraction of heat, should not alter the natural regime of temperatures or the distribution of nutrients within the expanse of water, nor should it disrupt conditions for living and reproduction of organisms, particularly in the riparian zone;
2. the oxygen content of the water should at no time and at no lake depth amount to less than 4 mg/l O2; in addition, it must be sufficient for sensitive animals such as worms to be able to inhabit the lake bottom throughout the year and in numbers as close as possible to natural abundance, subject to particular natural conditions.

2 Underground waters

21 General requirements

¹The concentration of substances in the groundwater for which requirements are specified in No 22 should not continually increase.

²The quality of the groundwater must be such that it does not pollute surface water after exfiltration.

³The introduction or withdrawal of heat must not alter the temperature of the groundwater by more than 3 °C above or below the temperature in its natural state; this does not apply to very local changes in temperature.

⁴Infiltration of wastewater into underground waters must not result in:

1. any disturbing change in the odour of the water;
2. any lack of oxygen or unfavourable pH values;
3. any turbidity or discoloration, except in the case of consolidated rock groundwater.

⁵Infiltration installations, withdrawals of water and other interventions connected with construction work must not, insofar as possible, damage the protective upper confining bed, or alter the hydrodynamics in such a way as to have detrimental effects on the quality of water.

22 Additional requirements for groundwater which is used for drinking water or is intended as such

¹The water quality must be suchthat after the use of basic water conditioning, it complies with the requirements of the foodstuffs legislation.

²The following numerical requirements apply, subject to the particular natural circumstances. For substances originating from polluted sites, these requirements do not apply in the downstream area where the greater part of these substances is degraded or retained.