Friday, September 16, 2016

Hitting the payload

My work centers around advising people where to drill wells, testing the wells for adequacy of supply and quality and explaining how it works in public forums. There are numerous misconceptions regarding the behaviour of groundwater in the Piedmont and Valley ridge provinces. But we're not going to get into that here-

Three weeks ago I was hired to find high yielding well in a particularly tough (geologically speaking) area of Virginia. Success  requires (1) experience, (2) a methodical approach and (3) commitment of time and resources. In this particular situation the work resulted in a well that possessed an "airlift yield" of approximately 250 gallons per minute -

Sunday, January 27, 2013

An Effort to Develop a Groundwater Supply in Nicaragua

On February 2, 2013 I will be traveling to Siuna, Nicaragua with the Charlottesville, Virginia based "The Building Goodness Foundation" (BGF) participating in an effort to develop a groundwater supply for a hospital. I am humbled (and flattered) to have been chosen as one of a team of five volunteers from Charlottesville working on this project.

My responsibilities will include "logging" the well cuttings (describing the geology, minerology, discrete water zones, etc), screen the water for contaminants, work with the drillers regarding casing length, total depth and pump depth setting (if we are fortunate to hit some water bearing zones). I intend to conduct a limited pump test and then collect the appropriate samples for laboratory analysis- But more on that in another Blog.

BGF has teamed with the Non-Government-Organization (NGO), Bridges to Communities (BTC) to restore clean water to the Siuna hospital that serves approximately 200 out patients a day.

For those of us who were assembling spitballs and twisting paper clips during geography class, the image below identifies Nicaragua's location on the Earth-(credit to GoogleEarth) :

And here is a closer look in relationship to some landmarks we are all familiar with from Nations on Line

Siuna is situated in the Region Autónoma Atlántico Norte (RAAN). The reader can find a link here describing this political region of Nicaragua.

It was described to me as a "frontier town" by one of the participants of this trip: cowboys on horses riding through the streets, etc. As described, the town is located in Northern Nicaragua- the image on the right shows its relative location in this region of the country. This map was "borrowed"-without permission (yet)- from a study I found on line that was conducted by some Dartmouth students in 2002. This interesting blog decribes some of the concerns about "heavy metals" that may be present from both natural and human-induced sources.

I hope to update this work several times while in the country and I also hope people feel free to comment. Those with experience in drilling water supply wells in the vicinity of mining regions-please do not hesitate to add your advice.

Monday, February 6, 2012

Decentralized Water and Waste- Honduras

These are a group of children from the community of Siete. Their family's homes were destroyed by Hurricane Mitch in 1998. There were about 400 disparate people/families from numerous locations that were "squatting" on this high ground when I visited there in December 2008. These are very poor people living on dirt floors with very poor sanitary conditions. Regardless, I was struck by their beauty, attitude, love and strong family bonds (picture below by Shin Fujiyama).
We were invited to Honduras to assist Students Helping Honduras. Mike Craun and I provided the expertise to assess the topography, drainage patterns, soils, and groundwater to design a decentralized water and waste water system(s) for a new community to provide homes for approximately 200 people.

When we were asked to assess the property, the project was in full swing. Nearly one-half of the buildings had been erected and plans included a huge soccer field, orphanage and school.
However, there had not been a survey, topography had not been "shot" and the "experts" here in the states didn't know the direction in which the land drained, nor did they know if a stream was present on the property. Still, the occupants desired in-door plumbing and there was no - nada- none-zero idea(s)of how to deal with the waste disposal for a community of 200 occupants.

Our team included Mike Craun, an experienced civil engineer with a strong background in public health and sanitary solutions, me- a geologist with experience in groundwater, public health and decentralized waste disposal and Antonio Martinez (background), an architect with loads of experience working with communities in central America. Antonio also acted as intrepreter.

One of the first tasks was to conduct a draw-down test on the
community well. In the picture on the right are members of the community getting ready to collect water samples for laboratory analysis. The well was pumped at a rate of 60 gallons per minute for an extended period of time and only experienced about 7 feet of total drawdown.

We then began to conduct a sanitary survey of the property and neighboring environs. In the upgradient position we found a village of 80 homes with living conditions that would offend even my own 1970's "back to the land" lifestyle. Waste water from the homes would simply be dumped in a drain and allowed to flow into the "street" and human waste was disposed of into a pit privy. Each home possessed a pit privy.
Down gradient were several springs. One is pictured here where women would come to wash clothes and collect water for drinking.

In the end a sewer system was designed that treated the waste to a high degree prior to discharge, a plumbing system was installed for both drinking water and toilets. The occupants built every last bit of it themselves and took control of every aspect of construction and organization.

Weekly community meetings were held reviewing accomplishments and what steps needed to be taken next. A great experience with some very loving, hard-working and community oriented people.

Saturday, January 21, 2012

Environment of Deposition- at the base of the Blue Ridge Mountains

I am currently working on an academic (or "geologic") problem at the base of the Blue Ridge Mountains in Rappahannock County, Virginia. I'll be working with Dr. Scott Eaton from JMU. The site is located on an "upland flat" on Route 231 between the Hazel River on the north and Hawlin Road on the south. Locally, this portion of Rappahannock County is known as F.T. Valley- named after Francis Thornton who owned a whole lot of real estate beginning sometime during the 18th century. He also owned the toll road crossing the Blue Ridge Mountains at Thornton Gap (see Figure below). While I couldn't find a lot of information about him, I found this Wikipedia Link about Thornton Gap which gives some information

This is unusual, but not unheard of, terrain in the eastern Blue Ridge Province of Virginia. There are several other similar areas close by: Banco/Criglersville, Etlan/Nethers, Sperryville and Gid Brown Hollow (near RT 211)- to mention a few.

The slope of the land in this particular area is approximately 2% (or less). I find that very interesting given the surrounding rolling and steep terrain that makes up this portion of the the Blue Ridge physiographic region. I suspect the flatness may be due several factors: perhaps erosion (not intuitively pleasing) or simply the uniform weathering of the bedrock (maybe); regardless, I want to find out (if possible) why it is flat. Is it coincidence that this upland flat is the "platform" for deposits of debris from the flanks of the Blue Ridge or are some thers factors at work?

Additionally, there are several (or more) terrace deposits on this platform/upland flat. I want to know what their relative ages and under what conditions they were deposited. Geologist now know that catastrophic rainfall events occur on a somewhat regular basis in the Appalachians and are responsible for many landscape forms (geo-morphology).

The photo above was taken in western Madison County, Virginia after the catastrophic (>30 inches in 16 hrs)rainfalls during June of 1995. Here is a link to Scott Eaton's paper on the Madison County floods of 1995.

Perhaps we may be able to determine how many episodes occurred here by studying the soils and their relative elevation with the Hazel River and to each other. Obtaining this information may help in predicting periodicity for this particular watershed and similar ones on the Blue Ridge.

Groundwater Lecture

I was recently reading up on Darcy's Law and ran across a series of lectures by Peter Cook presented at the Henry Darcy Distinguished Lecture Series in Groundwater Science. It is a three (3) part series: If interested: Here's a link to the first of the three:

Thursday, December 23, 2010

Groundwater for Irrigation

If you (or someone you love) are considering drilling a well for irrigation, please save yourself some money and collect some empirical information about your water supply. The only way to understand it, is to conduct some kind of "stress", "aquifer", or "pump" test on the water supply. There are number of sound reasons to conduct some kind of test on the well. But the number one reason I tell my clients is that it protects their investment.

As an example, look at the photo above. It was proclaimed that the well yielded "100 gallons per minute (gpm)". Really? For how long? "...well, for the 10 minutes we "blew" it out of the hole". Hmmm, ok.

Why spend $10K to $20K on a well, pump, piping and irrigation system to find out later that your 100 gpm well is really a 10 gpm well. The water is "the dog that wags the tail" for the entire enterprise; yet, I am amazed at the number of intelligent people who ignore the need to collect at least some minimum data regarding the capabilities of the aquifer beneath their feet.

I had a client who required 7500 gallons of water twice a week for his irrigation needs. He decided that before he invested an enormous amount of money for his irrigation system that he would have me conduct a limited pump test.

We first conducted a "STEP" test on the well. A STEP test is a "pre-test" for the main pumping event and is conducted to determine a pumping value for a longer period pump test. You start pumping the well at low rate- measure the drawdown and "STEP" it up after it appears it will hold. Here on the right is the graph of time vs drawdown for STEP test on this well. In this case we started at 5 gpm. This is a semi-log plot and it is clear that the well could handle 5 gpm (at least for awhile). So, we "stepped" up to 10 gpm. And the curve began to adopt an asymptotic shape. All good. Then we jumped it to 17 gpm. And lookie there!! It held steady at around 50 feet then the "angle" got a "little" steep. So steep that we needed to slow down!!! WHoaaaa Nelly!! So, we stepped back to 11 gpm and called it good for the day.

So, we allowed the well to rest from this activity and went back to work on the Alberene Soapstone patio in my yard (here on the right). This soapstone is a Proterozoic-age ultra mafic rock that was recrystallized by metamorphic processes. These emplacement "pods" make up a portion of the Lynchburg Group of rocks in central Virginia. Anyway, we went to quarry and bought several truckloads of scrap ($75/load)-hauled them back home and cut them with a wet saw that belongs to Terry Waggener (seen in previous post). He is a lengendary stone mason who knows more about geology than most graduate students (certainly more than me). The retaining wall in the background was made from precambrian-age granite gneisses, cambrian-age catoctin greenstones and the base layer were rocks from the arkosic sandstone/quartzites of the Lynchburg group (similar age as the soapstone).

Back to the test: we
returned to the property to conduct a limited withdrawal of the well only to find everything frozen up and had to spend several hours unthawing the pipes.

Sunday, December 12, 2010

Petroleum Storage Tanks and The Virginia Reimbursement Program

The state of Virginia operates a program that reimburses homeowners and businesses for expenses of cleaning up legitimate tank leaks that are considered a threat to the environment or human health. Please follow the link on my website to learn more about the program (VPSTF). Most of us (tank owners) will have no reason to suspect that our tanks are leaking unless our fuel bills increase unexpectedly or if they come to the attention of professionals hired to screen environmental threats. In the picture to the right is my pal, Terry, posing next to an underground storage tank with an auger in his hand. The fill pipe is sticking up out the ground to the right. True North was hired to determine if there was any evidence to suggest that the tank had leaked. The Tank Fund is there because it is expensive to clean up spills from these leaking tanks. Anyone buying gasoline in the state of Virginia contributes (unwittingly) to this fund. It has made it possible for homewoners to rectify environmental hazards on their property and in so doing protecting their real estate investment. And the homeowner is only
out $500 - and sometimes less-. The reason for this is that environmental consultants are eager to perform this work and will usually waive the $500 fee just to have the work (yes, including us!!). A whole industry has sprung up that represents the interests of the homeowner (one hopes) and conducting the cleanups and working with DEQ to make sure the job gets done.

We recently were hired to conduct an environmental screening of the property above. A part of this work included soil around a buried gasoline tank. Field observations and laboratory analysis indicated that the soil was clean. After the property was purchased the owners hired True North to supervise and document the removal of the gasoline tank. Everything looked good and the tank removals proceeded swimmingly. For those interested heres a video of a portion of the tank removal. PLease forgive the language- we're just a bunch of unrefined good 'ol boys- so please excuse the profanity.....