Lower Milford Township

At the Curative amendment Hearing on June 30, 2009, Mr. Ross, the consultant for Gerryville Materials, indicated that they intended to pump over 340,000 gallons/day of water from the site. Because of the quality of the Hosensack stream, they did not want to put it in as a point source. Rather, they will infiltrate the water back into the ground through a series of perforated pipes. This technology has never been employed in a quarry type setting before.

This raises some serious concerns. The irrigation system proposed is used in some other applications most notably farming. However, the duration of the irrigation and the periodicity of irrigation can be significant in the feasibility of this approach.

 

The Process

In a typical infiltration system, a series of perforated pipes are placed either above or below the ground. Water is pumped into the the pipes where it leaks out into the ground. The water then flows through the ground until it reaches an aqifer below. This enables the water to be filtered by the ground, removing particulate and other pollutants. 

The ability to successfully replace the water depends on a lot of factors such as the nature of the earth, e.g., water will pass through sandy soil much more rapidly than through clay, the distance between the water and the aquifer, etc. The flow has to be by gravity. Pumping could cause channeling and destroying the ability of the land to purify the water. Percolating through the ground reduces the chances.A very rough calculation would indicate approximately 10 -20 acres of land would have to be devoted to infiltraton.

Concerns

• Is there sufficient space available to do proper infiltration?  If one takes into account slopes, streams and the condition of the land, is there enough area available to ensure water will go down to the proper aquifer? If near a slope or the Hosensack, water could spread and runoff the slope or enter the Hosensack. This could damage water supply downstream.
• What type of land is available for infiltration and is it suitable for long term infiltration? For example, clay will swell and tend to shut off water flow if used without allowing for drying. Loams could compact or eventually channel.
• Does continuous use change the parameters of engineering models thereby affecting ability to process water? If one saturates land for many years does the ability of water to drain get affected?
• How much of the community depend on the water being pumped?If a significant amount of this water is used for community use, does it make sense to risk it by applying an unproven process? What direction does this water normally flow?
• What is the possibility that silt from the water and pollutants will either plug or saturate the land making process inefficient or inoperable? This is a process that will operate continuously for years. This is a high risk process when unproven and can affect many families.

Conclusions

The infiltration process being proposed has not been applied to quarries. Irrigation processes on farms operate very differently from a continuous drainage process required here. It is not directly transferable to this situation. Gerryville Materials did not state what other applications use this technology. Existing tests, e.g., ASTM standards do not seem applicable to this situation. It would seem that this is a very high risk technology to apply to an area where a large population can be adversely affected.