Applications
What does a typical VECTOR application look like? The VECTOR can provide a user with such a variety of highly detailed data that there really is no standard application. Frequently, users install the VECTOR with a simple application in mind, such as assisting in characterizing a ground water regime. Once data is collected a user will realize that the VECTOR can obtain detailed pump test data: turn on a nearby well pump and watch, in real time or otherwise, ground water change direction and magnitude, or not, thus providing tremendously valuable data for designing, testing, and monitoring remediation systems. Following the installation of a remediation system, the VECTOR can be used to prove its efficacy over days, or months, or even years. So, there it is, a single VECTOR application that results in three. However, some users will purchase a battery of VECTORs with the specific intent of testing a new and complex remediation system. In this case, an aquifer has been well characterized beforehand; VECTORs then provide a detailed three-dimensional framework from which the remediation system performance can analyzed. But that's just for remediation . . . consider the limitless applications from ecology to dam safety.
What lithologies can the VECTOR be used in? The VECTOR obtains excellent results when emplaced in what the U.S. Department of Agriculture calls "sand". This loose rubric of "sand" includes any material grain sizes from 0.050mm to 1.5mm or U.S. Standard Sieve Series No.270 to No.12. Usable results, however, have been obtained from lithologies well past these end members. For the technically minded, the VECTOR® assumes, when calculating its algorithm, any homogenous, saturated lithology to an infinite radius whose thermal and hydraulic properties are both isotropic, homogenous and valid for Peclet numbers to order 1.
What lithologies can't the VECTOR be used in? Any lithology that precludes a laminar groundwater flow past the probe surface is inappropriate for the VECTOR. Fractured or solid bedrock, unsaturated sediments, excessively high ground water flow velocities or grossly heterogeneous lithologies primarily consisting of cobbles and coarse glacial deposits will yield poor results. Conversely, super fine sediments such as silts and clays will also yield poor results in that heat from an activated probe will not be carried past the probe surface faster than it can rise upward. However, thin lenses of these kinds of sediments within an appropriate lithology can be accounted for when performing data analysis by simply isolating those thermistors in direct contact with the lenses. This, of course, assumes that probe emplacement has disturbed little of the surrounding lithology. Where this is impossible, the VECTOR's many built-in redundancies makes correcting for anomalous results as simple as switching off bad light bulbs.
Can the VECTOR be used in an open or screened well? Not yet. Although the VECTOR was originally designed for emplacement in direct contact with a saturated granular lithology, efforts are underway to produce a tool that will measure 3-D flow within any borehole configuration. Other technologies exist for measuring ground water flow in screened wells though it is important to recognize that well construction influences the movement of ground water through a screened borehole. Aquavision manufactures the Colloidal Boroscope: a camera tracks the horizontal movement of suspended particulates inside a one cubic millimeter volume within an open well. A technician lowers a camera into a well and tracks the minute movements of suspended particles; computer software then converts those tracks into a velocity. The camera is then removed and brought to the next well for another reading. Another manufacturer uses a heat pulse to obtain either horizontal or vertical velocities. Neither of these technologies samples as large a volume as the VECTOR, nor do they provide the long-term monitoring capabilities that the VECTOR can. In addition, neither of these tools simultaneously resolves both the vertical and horizontal components to ground water flow.
What is the best method of drilling for probe installation? Hollow-stem augers have so far yielded the best results. Although messy in that copious cuttings are produced and the (local) lithology gets disturbed, this method offers a good guarantee that the lithology will uniformly collapse around the tool when the auger flights are removed. Good results have also been obtained using mud-rotary methods, as well. VECTORs installed with ResonantSonic Drilling technology indicate that this method may, in the future, provide an excellent alternative to the hollow-stem auger.
Is this a proven technology? Absolutely. The VECTOR has been thoroughly field tested in a variety of field conditions by national labs and universities. In a 1997 Geological Society of America Environmental & Engineering Geoscience paper, Texas A&M University researchers assessed river-floodplain aquifer interactions using both the VECTOR and conventional methods . In these early tests, two VECTORs were installed in the banks of the Brazos River along with a battery of surrounding piezometers arranged in well-nests. Impressed, researchers discoverd that not only did the VECTOR provide similarly interpreted data as the piezometers, it provided that data directly, instantaneously, and continuously. Please see the Publications for selected summaries of past VECTOR projects.
Can the VECTOR be re-used for another project? Certain components of the tool may be re-used. Unfortunately, probe sensitivity and sensor robustness are mutually exclusive given the current state-of-the-technology. Once emplaced, the probe part of the VECTOR system would likely be damaged by removal although there's no reason why the probe couldn't be re-used in another location if it were removed without damaging the thermistor covering. However, Hydrotechnics does not recommend risking the high drilling expense of installing a potentially damaged tool.
What do I have to provide for a VECTOR installation? When a HT technician arrives on your site, he (or she) will expect, at a minimum, the probe and all peripherals as they were shipped to you, nearby electrical power, drilling services that you have contracted, the correct lengths of threaded PVC pipe for all probes, and, above all else, your assurance that the subsurface lithology is appropriate for VECTOR installation. You, however, can expect an HT technician to install the probes at the requested depths, connect all peripherals, and power up the system. The technician will also provide all software as well as a mini tutorial on system operation. Bear in mind that we can provide you with as much service as you need.
Does Hydrotechnics have to install my probes? Nope. Installing a VECTOR is relatively simple for anyone who has experience installing monitoring wells or piezometers. Setting up and calibrating the system is also relatively simple provided that the instructions are carefully followed, though some facility with computers is required. In addition to the detailed manual, we are always available to help you out via telephone and e-mail during any phase of the installation. Many of our clients, however, dispense with the bother of installation by contracting HydroTechnics to come to their site and get their system up and running. Some also contract us to collect their data and provide timely interpretive reports. We do, however, suggest that you watch a HT technician install your first VECTOR if you haven't seen the process before.
What kind of warranty covers the VECTOR? HydroTechnics can only warranty the products we build, namely, the VECTOR. The probe is officially warranteed for 90 days though unofficially for much longer: one probe operated in acid nearly a full year before an explosion at the nearby refinery cut off the local ground water flow. Other parts such as power supplies and data loggers have standard manufacturers warrantees. Although the software itself has a standard industry warranty, that is, none, we at HydroTechnics have always stood by our product guaranteeing that if you get something that doesn't work, we'll replace it.
If I install my probe myself, will that void the warranty? Yep. We have no control over where or how you install your probe. In addition, you might accidentally install a probe that has been damaged by shipping (it hasn't happened yet). Only HydroTechnics can certify that the VECTOR you receive is in good working order and has been correctly installed in an appropriate environment.
I have a project planned, when is a good time to get my VECTORS installed? Although this is not a "Frequently Asked Question", it should be. Following the installation of exploratory boreholes to establish groundwater depth and lithology, the VECTORs really should be the very next things to go in the ground. This sequence of events allows one to establish the baseline conditions around which the future of the project is designed. Few project designers realize the power of the data collected by the VECTOR until later when establishing baselines is difficult or impossible, thus negating one of the primary benefits of this technology. If you have a remediation system to be tested or a resource to be monitored, make certain that you plan for VECTOR installation well before your system installation; it will greatly facilitate data interpretation.
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