Chamber and committees

Given that sustainable urban drainage systems are common practice in all new developments, the expectation is that the figures quoted in the answer given to question S1W-29075 today, will increase. The SNIFFER project referred to in that reply has estimated there will be some 1,600 SUDS sites in Scotland by January 2006.

Scottish Water carried out 484 tests for cryptosporidium on the treated water at Milngavie treatment works between January 2002 and August 2002. One hundred and sixty-seven of these test results were positive. The maximum level of Cryptosporidium detected in the treated water over the period was 0.353 oocysts per 10 litres and this was reported on Saturday 3 August 2002.

Postcode EH9 covers two water quality zones, one supplied from Alnwickhill water treatment works and the other from Fairmilehead.The August results for the zone supplied by Alnwickhill show that one sample contained 101.6 microgrammes per litre of trihalomethanes (THMs). However, the standard for THMs set in the Water Supply (Water Quality) (Scotland) Regulations 1990, of 100 microgrammes per litre, is based on a three month rolling average. The results for June and July were 95.1 microgrammes per litre and 98.5 microgrammes per litre, respectively. The THM standard, based on the three month rolling average, has therefore not been breached.

During the 12-month period from 1 September 2001 to 31 August 2002, Scottish Water carried out 730 tests for cryptosporidium on treated water samples taken from Milngavie treatment works. A total of 243 of these tests were positive.The Cryptosporidium Direction requires Scottish Water to report results as "oocysts per 10 litres". At no time did the level of cryptosporidium in the water leaving Milngavie exceed 1 oocyst per 10 litres. The maximum number of oocysts detected in the treated water at Milngavie was 0.353 oocysts per 10 Litres and this was reported on 3 August 2002.

Planning Advice Note 61, Planning and Sustainable Urban Drainage Systems was published in July 2001. It gives advice on the role of the planning system in helping to deliver sustainable urban drainage systems (SUDS) as advocated in the SUDS Design Manual for Scotland and Northern Ireland.The SUDS Monitoring Project, funded by the Scotland and Northern Ireland Forum for Environmental Research (SNIFFER), shows 3,913 systems installed on 769 sites during the period between mid-1995 and the beginning of 2002. Since most of these will predate the publication of the Planning Advice Note (PAN), it is not possible to say what effect publication of the PAN has made.

Each regulatory authority has its own powers, and thus formal approval for a drainage system may be needed from the planning authority (planning permission); the building control authority (building warrant); Scottish Water (drainage construction consent); the roads authority (road construction consent); and from Scottish Environment Protection Agency (SEPA) (consent to discharge - if required - or conditional prohibition notice).The developer is responsible for the construction of a sustainable drainage system and for ensuring it meets the requirements of the design manual prepared by the Sustainable Urban Drainage Scottish Working Party. As described above, depending on the circumstances the developer may have to ensure that the appropriate local authority, SEPA and Scottish Water are content with the design of the system.

The Drinking Water Quality Regulator, the Water Industry Commissioner and the Scottish Environment Protection Agency each have a duty to ensure that the regulatory framework is operated in accordance with the requirements of the Parliament.

The answer given to question S1W-26583 pointed out that the effectiveness of the treatment process proposed for Milngavie, like all treatment processes, was dependent on the monitoring and control regimes put in place, but that Scottish Water planned to operate the new works in accordance with industry best practice.The proposed process is similar to the process used at the Balmore water treatment works which treats Loch Lomond water successfully. The process is used widely for the treatment of upland waters typical in Scotland and other similar parts of the United Kingdom e.g. Watchgate in Manchester. The suitability of the process for Loch Katrine water, including its ability to remove cryptosporidium sized particles, has been proved in extensive and independently verified pilot plant trials.

There was no outbreak of cryptosporidiosis in Glasgow in August 2002. The monitoring system detected increased levels of cryptosporidium in the public water supply and precautionary advice was issued to boil the water before use. This precautionary advice may have prevented an outbreak.

Until a new water treatment plant is commissioned, the public in Glasgow remains at risk from cryptosporidium in the water supply. To minimise this risk, Scottish Water has reduced the number of sheep grazing on the land owned by Scottish Water around Loch Katrine and all sheep owned by Scottish Water will be off the catchment by the middle of this month. It is because of this risk that continual monitoring takes place. However, cryptosporidium is ubiquitous in the environment and can be carried by wild animals as well as farm animals.Scottish Water is also constructing a pipeline to bring treated water from Balmore water treatment works into the Glasgow area. This will have the effect of reducing the size of the population exposed to the risk from cryptosporidium by about 90,000 people.