Developing an Assessment Monitoring Plan
In accordance with given assignment, it is necessary to develop an assessment monitoring plan for hazardous waste storage site located in the Piedmont physiographic province of North Carolina. In order to perform it, it is recommended to follow next steps: define a problem and what method of monitoring will be used, what materials or samples to be monitored, identify location for conducting observations, time for monitoring or periods of taking samples and designate responsible staff for this type of work. Thus, using information given in assignment it is possible to determine these steps.
To start with, the reason of developing as assessment monitoring plan consists in obtaining and analyzing information regarding soil and water quality in a place where site experienced a significant spill from 5,000 gallon holding tank in one of the buildings. It is defined that approximately 50% of 40-acres area was affected by the spilled substance, which is a semi-volatile organic suite of chemicals. Type of soil influenced and distribution of different layers of materials, including depth of water layer, is defined next.
The top of the water table in the aquifer is 40'. With respect to the assignment the geology is uniform across the site as follows: 0'-18' silty sands; 18'-20' feet clay; 20'-35' sandy silty; 35'-45' is a saprolite (severely weathered rock which can allow water to pass through it); 45' - 65' more saprolite (this time, less weathered, more competent), and finally, at 65' competent bedrock. To determine numbers of wells and if applicable, surface water monitoring stations, it is necessary to estimate time of spreading allocated waste across the area and necessity of setting additional equipment for monitoring water surface (Bloetscher, 2007). Regarding this appliances it should be noted that its need directly depends on whether there are any surface water. If not, it is not required and recommended, since it will lead to additional expenditures and investments in project.
However, if there are any sources or locations of water in some places, it can be quite pertinently to install several measuring devices to control amount of hazardous substance (Alth, 1992). Their number can hesitate dependently on the area that possibly hazardous water takes and frequency of appeared sources. Talking about wells, their numbers depend on the depth of the hazardous waste contamination and the area of spread. Since the total square of split material is approximately20-acres or ~0.004sq. kilometers, which are 4000 sq. meters, recommended lateral spacing among installed wells is considered to be about 50 meters. Then it is possible to install 80 wells to provide quality and detail monitoring of soil conditions all over the split area. Defining depth, it could be possible that it value would vary for each well, but, since the geology is uniform across the site, its meaning is going to be the same for each separate well. Wells should be placed, as it was mentioned before, not far from each other, being located near the main locations of contamination (Heck, 1994).