• Giving full consideration to representative monitoring wells and scientific well
deployment, and making full use of existing monitoring wells. If the quantity
and quality requirements cannot be met, additional monitoring wells need to be
deployed;
• Making prospecting sites denser in areas prone to leakage and pollution diffusion as the liners of landfills are met or folded;
• Extending or reducing the distance between monitoring sites and landfills
according to factors such as the natural environment, topographical features and
hydrogeological characteristics of the site;
• Where there are springs near the sites, using upstream springs for monitoring
site background and downstream springs for monitoring pollution diffusion;
• Deploying monitoring wells based on existing monitoring network and historical monitoring of groundwater quality (or based on groundwater vulnerability
assessment) in the sites;
• Setting groundwater monitoring sites in the karst area along the groundwater
channel that is closely related to landfills.
(2) Deployment method
(a) Standard MSWLFs
• Pore water in plains and gentle plateaus
– One of landfill boundaries is perpendicular to or forms a minimum angle of less
than 10° with the direction of groundwater flow.
A site background monitoring well is laid in the upstream, 30–50 m from the
landfill;
Among the five pollution diffusion monitoring wells, one is installed 30–50 m
from landfill boundary on each of the two sides, in the direction perpendicular to
groundwater flow. In the downstream, two are installed 30 m from the lower
landfill boundary and 30–50 m from each other, and one 50 m from the lower
landfill boundary, as shown in Fig. 2.3.
– One of landfill boundaries forms a minimum angle of greater than 10° but less
than or equal to 45° with the direction of groundwater flow.
A site background monitoring well is laid in the upstream, 30–50 m from the upper
vertex boundary of the landfill.
Five to six pollution diffusion monitoring wells are installed with an equidistant
spacing of 30–50 m in the downstream, 30–50 m away from and perpendicular to
landfill boundaries, and one set in the downstream, 80 m from the lower vertex
boundary of the landfill, as shown in Fig. 2.4.
• Karst water and fissure water in mountainous and hilly areas
A site background monitoring well is set in the upstream, 30–50 m from the landfill
boundary. Upstream springs with close hydraulic relation to the site, if any, can be
used for monitoring site background;
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2 Environmental Background Investigation of Groundwater …
deployment, and making full use of existing monitoring wells. If the quantity
and quality requirements cannot be met, additional monitoring wells need to be
deployed;
• Making prospecting sites denser in areas prone to leakage and pollution diffusion as the liners of landfills are met or folded;
• Extending or reducing the distance between monitoring sites and landfills
according to factors such as the natural environment, topographical features and
hydrogeological characteristics of the site;
• Where there are springs near the sites, using upstream springs for monitoring
site background and downstream springs for monitoring pollution diffusion;
• Deploying monitoring wells based on existing monitoring network and historical monitoring of groundwater quality (or based on groundwater vulnerability
assessment) in the sites;
• Setting groundwater monitoring sites in the karst area along the groundwater
channel that is closely related to landfills.
(2) Deployment method
(a) Standard MSWLFs
• Pore water in plains and gentle plateaus
– One of landfill boundaries is perpendicular to or forms a minimum angle of less
than 10° with the direction of groundwater flow.
A site background monitoring well is laid in the upstream, 30–50 m from the
landfill;
Among the five pollution diffusion monitoring wells, one is installed 30–50 m
from landfill boundary on each of the two sides, in the direction perpendicular to
groundwater flow. In the downstream, two are installed 30 m from the lower
landfill boundary and 30–50 m from each other, and one 50 m from the lower
landfill boundary, as shown in Fig. 2.3.
– One of landfill boundaries forms a minimum angle of greater than 10° but less
than or equal to 45° with the direction of groundwater flow.
A site background monitoring well is laid in the upstream, 30–50 m from the upper
vertex boundary of the landfill.
Five to six pollution diffusion monitoring wells are installed with an equidistant
spacing of 30–50 m in the downstream, 30–50 m away from and perpendicular to
landfill boundaries, and one set in the downstream, 80 m from the lower vertex
boundary of the landfill, as shown in Fig. 2.4.
• Karst water and fissure water in mountainous and hilly areas
A site background monitoring well is set in the upstream, 30–50 m from the landfill
boundary. Upstream springs with close hydraulic relation to the site, if any, can be
used for monitoring site background;
18
2 Environmental Background Investigation of Groundwater …