RESERVOIR WATER QUALITY SAMPLING DESIGN¹

Abstract

The design of monitoring programs often serves as one of the major sources of error or uncertainty in water quality data. Properly designed programs should minimize uncertainty or at least provide a means by which variability can be partitioned into recognizable components. While the design of sampling programs has received recent attention, commonly employed strategies for limnological sampling of lakes may not be completely appropriate for many reservoirs. Based on NES data, reservoirs are generally larger, deeper, and morphologically more complex than natural lakes. Reservoirs also receive a majority of their inflow from a single tributary located a considerable distance from the point of outflow. The result is the establishment of marked physical, biological, and chemical gradients from headwater to dam. The existence of horizontal as well as vertical gradients, and their importance in water quality sampling design were the subject of intensive transect sampling efforts at DeGray Lake, a U.S. Army Corps of Engineers reservoir in southern Arkansas. Data collected were used to partition Variance, identify areas of similarity, and demonstrate how an equitable sampling program might be designed.

Spatial and temporal heterogeneity in a subtropical reservoir and their effects over the benthic macroinvertebrate community

“…This gradient leads to the distribution of the communities into environmental compartments (Thornton et al, 1982).…”

Water management plan for olive orchards in a semi-mountainous area of Crete, Greece

“…In this way, many areas can be protected from an oncoming extreme hydrological event (flood -drought). In addition, from an ecological and environmental point of view, these hydraulic structures should be designed and operated to collect only part of the surface water in order to avoid drought conditions at the downstream sections of the river (Thornton et al, 1982). Based on the above, and taking into consideration the 2D modeling time-space flow accumulation results, different locations for the construction of small scale hydraulic structures can be proposed.…”

Seasonal and longitudinal variations in apparent deposition rates within an Arkansas reservoir1

“…These hydrodynamic characteristics, and the transport and sedimentation of influent materials, provide a physical setting that fosters the establishment of physical, chemical, and biological gradients from headwaters to dam (Baxter 1977;Gloss et al 1980;Kennedy et al 1982;Thornton et al 1982). Although such water quality gradients have been documented in reservoirs, there is little information regarding similar patterns in sedimentation rates (Hakanson 19 76;Pharo and Carmack 1979).…”

“…Riverine influences become less pronounced down-reservoir due to sedimentation. De- position of allochthonous material to the sediment surface is probably minimal at the river mouth because of strong turbulence (Kennedy et al 1982). Maximal deposition would occur when advective velocities decrease near the plunge line.…”

“…Autochthonous productivity and deposition are generally low near the river mouth since the influx of turbid water limits available light (Gloss et al 1980;Kennedy et al 1982). Light penetration increases as suspended particles settle from the euphotic zone, stimulating productivity when nutrient conditions are favorable.…”