the bathing area. Land-based sources of contamination are normally associated with smaller discharges or with the likelihood of heavy rain events, characteristic of the Mediterranean climate at the end of the summer period, where a great amount of water falls in a very short period of time. Heavy rain may wash out faeces from pastures or other agricultural land and directly influence microbiological water quality. Studies in other regions also document pulses of poor water quality associated with rainfall events (O'Shea and Field, 1992; Vonstille et al., 1993; Armstrong et al., 1997; Wyer et al., 1994, 1995, 1997). In inland recreational waters the main sources of pollution are water inlets (PHLS, 1995). Therefore, influences from rivers, natural watercourses and, particularly around populated areas, combined sewer overflows, produce important changes in the microbiological quality of bathing waters. Sporadic malfunctioning of sewerage systems can produce similar problems (Davis et al., 1995; Marsalek et al., 1996). These events, if recent, can sometimes be recognised visually at the recreational site by changes in the appearance of the water. In marine recreational waters, a field analysis of the salinity can indicate the discharges of freshwater at the bathing site. Such measurements indicate indirectly, that land-borne discharges are occurring.
8.1.1 Pre-inspection preparations
The collection and review of any existing data or reports on the area, including reports of previous inspections, will allow a thorough and efficient on-site evaluation. Topographical maps and aerial photographs are useful tools for locating activities and features that could affect water quality and for establishing sampling sites. Historical data on tides, currents, prevailing winds, rainfall and discharges of sewage, storm overflows and combined sewer overflows, and urban and agricultural effluents should be collected and reviewed to determine the impact of these events, (either singly or collectively) on water quality. Depending on the availability of water quality data, experts conducting the annual inspection may need to collect samples for microbiological analyses. Therefore, adequate numbers of sterile sample bottles and sampling equipment should be readily available and prior arrangements should be made with the microbiology laboratory to process samples promptly after collection. Arrangements should be made to meet with user groups and with individuals in charge of any facility or activity that affects, or has the potential to affect, water quality in the recreational area. It will be essential to obtain the trust and co-operation of the groups or individuals if the survey is to provide an accurate assessment of water quality and to identify and remedy unacceptable water quality (see Chapter 6).
8.1.2 On-site visit
The purpose of the on-site visit is to identify and evaluate all existing and potential sources of microbiological contamination that could affect the safe use of the area. Attention should be paid to the presence of sewage disposal facilities, including long sea outfalls, industrial outfalls, seabird colonies, sanitary sewers, and rivers, tributaries, streams or ditches receiving sewage, storm water or agricultural runoff. All data recorded should be added to the catalogue of basic characteristics to form a catalogue of inspections that would enable the tracking of trends and influences (see Chapter 2).
Visual faecal pollution (including sanitary plastics), sewage odour and suspicious water colour should also be considered as an immediate indication of unacceptable water quality. Adjacent industries should also be identified and their impact assessed. The