Establishment of the Sediment Monitoring System for the Sava River Basin - page 03

 

Basic Considerations on the Establishment of Sediment Monitoring

An effective monitoring program consists of the following steps: (1) Choice of meaningful and attainable monitoring objectives, (2) The development of a monitoring plan, and (3) Design of a proper sampling strategy and method (Reuther, 2009).

Reuther (2009), AMPS group (2004) and Ongley (1996) confirmed that the sediment sampling is a major step for an effective monitoring program. Sediment samples should be collected at an appropriate frequency, taking into account the sedimentation rate and the hydrological conditions such as a flood event. The methods and equipment used for sampling suspended sediment are different from those used for deposited sediments.

The measurement of sediment transport requires that many simplifying assumptions are made. This is largely because sediment transport is a dynamic phenomenon and measurement techniques cannot register the ever-changing conditions that exist in water bodies, particularly in river systems (Brils, 2008).

 

Density of Sediment Monitoring Network

Design of sediment monitoring networks is based on the minimum density principle, either by measurement of the erosion, transport and deposition of the sediment within the country, or by measurement the total sediment discharge into the sea.

 

An optimum network would contain a sediment station at the mouth of each important river.  Streamflow records must be collected at all stations where sediment transport is measured. Therefore, the sediment transport monitoring stations should be so located that they can function as components of the minimum streamflow networks.

WMO (1981) recommends that sediment transport should be measured on 30% of the stations in the minimum network of stream gauges in arid/Mediterranean regions, and 15% in humid regions. The minimum density of hydrometric (stream gauging) stations the minimum density required is 1000-2500 km2/station in flat regions of temperate or Mediterranean zones, 300-1000 km2/station in mountainous regions of temperate or Mediterranean zones, and 5000-20000 km2/station in arid zones. From the two aspects one can conclude that under European normal conditions the minimum sediment monitoring network-density is between 1000-3000 km2/station for normal conditions and 3000-10000 km2/station for extraordinary conditions.

 

International Standards for Sediment Monitoring

Some international standards for suspended load and bed load monitoring, as well as standards for sediment quality monitoring are already available, as presented in Table 1.

Tab01