Setting Well Points and Other Prep

The last two weeks have been mostly about preparation. There has been a little bit more of the pond dug. Most of the dirt moving involved filling is some of the former agricultural ditches and rerouting others to help take care of the site runoff during construction. Primarily, though, the contractor has been busy accepting deliveries of materials and moving those materials to appropriate storage areas. Lots of concrete stormwater pipe and stormwater boxes are now on site, as well as much of the sewer and water pipe. Sewer pipe is green and water pipe is blue. These colors are standard for these utilities. When you see utilities marked in Habersham prior to some work being done, you’ll often see green and blue spray paint on the ground. Green is marking where there is a sewer pipe underground and blue a water pipe.

What the pond looks like this week

Stormwater boxes of all different sizes lined up, waiting to be put in the ground.

Water pipes stacked up in the distance along with other materials for water and sewer installation

Concrete stormwater pipes

Various materials recently unloaded from a truck

First delivery of green sewer pipes on site.

These types of material deliveries are very time consuming. They require big equipment to unload the trucks because of the size and weight of each object. Then, each item has to be carried individually to where it will be stored. Organization is important as the size and weight of these materials make it not easy to just move around if they end up being in the way.

The most interesting work that took place a couple of days is setting well points for the preparation of digging the deep hole for the wet well, which was described in the previous blog post. Well points can be thought of as vertical French drains that use a pump to bring water up. A 2” pipe that is 30’ long is inserted straight up and down into the ground. At the bottom of the pipe, the end is capped and there are small slits in the bottom 2’ of the pipe. The top of the pipe is above ground and connected to a larger pipe that is connected to a pump. The pump creates a vacuum in the pipe which draws groundwater in through the slits and sucked up into the larger pipe, which passes through the pump and is pumped out to the neighboring pond. Many of these are placed every few feet around the perimeter of the hole you need to dig and all connected. The goal is for these pipes to suck the ground water out of the area you will be digging so that you are not battling water when you dig beyond the water table. We’ll find out if it worked when the wet well is dug!

The video below shows how this work is done. What you’re seeing in this video is an excavator with a special ram rod hung from its bucket. The ram rod has water pumped through it and is constantly shooting water out of the end. As the excavator rams the rod down into the ground, the water jet is displacing the soil. The video starts with the ram rod being pulled out and then immediately moving to the next location. As the rod is pulled out, the crew quickly pushes one of the yellow pipes down into the hole. You can see how far down these pipes go. Some rock or sand is dumped in afterwards to help keep the slots from getting clogged with dirt. This process is repeated to border the future hole on 3 out of 4 sides with well points every couple of feet.

The picture below shows the finished product. You can see the tops of all the yellow pipes are connected to the larger perimeter pipe laying on the ground, which is connected to the pump. Each of those yellow pipes has water being pulled up from 20’ down and that water is being pumped into the pond next to it. Hopefully this will make it easier to dig in a few days.

Once the well points were set, the crew began putting together something called a trench box. This trench box, shown below will be lowered down into the bottom of the hole once it is dug and create a safe place for people to be down in the hole working to set the wet well. Everything is prepared and the next blog post will hopefully show the wet well being dug!