VDOT Update March 18 2019 for Glebe Harbor Dr

Early yesterday morning, March 18th, 2019, I stopped and talked to VDOT as they were working on Glebe Harbor Dr. We were discussing our drainage issue and what could be done about it. They informed me that the stretch of Glebe Harbor Drive between the entrance signs and 1500 feet past them towards the clubhouse, only had an elevation drop of 2 inches. In other words, the road/ditch line, is pretty well flat.

If you think about the septic drains in your home, most of the drains run on a downward grade anywhere between a 1/4 and a 1/8 inch per foot. If the grade is to shallow then the waste and paper will start to build up and your pipe could get clogged up. To the best of my knowledge, that is where the old saying of “water does not run up hill” comes from. If the grade is to steep, then all the liquids will drain to fast leaving the waste and paper still sitting in the pipes. Again, if this happens it will only be a matter of time before the pipes become clogged up.

Believe it or not, both outside ditches as well as house drains are what is referred to as “non-pressurized” drain systems. If you look at the roof of any home, you will see the plastic pipes that can be seen sticking up past the roof. This is simply a vent that allows air to be introduced into the drain pipe as the contents are being flushed out of the drain system. If you clog up the vents, the drains will start to back up. So why does this matter?

When it comes to ditch lines, there are several parameters that must be met in order for the ditch to drain properly. One of the main requirements is proper elevation of the ditch line. One end must be higher then the other as “water does not run uphill”. Then you must factor in keeping the ditch free from debris as well as what the average water table is for our area.

As a rule of thumb, the closer you are to a water source, the higher the water table. Determining the water table is very simple. Take a shovel and start digging a hole. When it starts to fill up with water, that is your water table height. You need to realize that depending on the type of soil as well as the average rainfall, will also have a impact on the height of the surrounding water table as well. During a drought, the water table will be much lower then during a period of days/weeks of rain.

So after knowing all of this information, it is very easy to see that due to the flatness of our problem areas, the decades of neglect as far as keeping our ditch lines/culverts cleaned out and our proximity to surrounding water ways, (our high water table), our problem areas simply do not meet the three most important factors, for proper ditch line drainage.

There is a reason all the land on the left coming into Glebe Harbor, as well as parts of South Glebe Rd and Machodoc Dr have very few homes built towards the entrance of Glebe Harbor. (the lower side). When it rains this area has standing water. When it rains for days, this area floods. It is my opinion that this issue will never be resolved as it has been this way for close to 50 years and the cost would be astronomical to regrade our ditch lines.

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