Conducting outdoor field work in the winter months often presents many obstacles. Whether it’s a drilling program, an excavation, or just groundwater sampling, outdoor activities all present their own unique challenges. Cold weather challenges are typically associated with significant snow and ice accumulation or very low temperatures and may be technical in nature or could relate to health and safety issues. With proper planning though, these issues can be addressed and warmth can be conserved during the winter.
When outdoor temperatures fall significantly below freezing, technical impediments can arise when conducting operations that rely on flowing water. Groundwater sampling in particular, especially when using low-flow methods, can become very difficult as the water being extracted from the ground can freeze easily, preventing sampling. This can also happen during in-situ remedial injection programs that rely on the flow of reagents into the subsurface. In both of these cases, the best way to keep water from freezing and things flowing smoothly is to avoid stopping the flow of water for any period of time. If it is cold enough, even a few minutes without flow can cause water to freeze in the lines which could result in major delays, prevent the completion of work, and even cause damage to the equipment. While groundwater sampling, pumps should be kept continually running at a sampling location until all samples from that location are collected while purged water is collected in buckets and stored in drums. For injection programs, the use of re-circulation pumps can be used to keep water and reagents flowing between injections.
Cold temperatures also present health and safety issues in many scenarios. The most common issue for field staff is the potential for frost nip or frost bite on the hands. Virtually all field scenarios involve sampling or equipment manipulation of some kind, which can be very cumbersome with heavy gloves on. In particular, nitrile gloves are worn during sampling and often do not fit over other, warmer gloves. This leads to the removal of warm gloves to carry out sampling using nitrile gloves, and if one is not careful, this can quickly lead to warmth and circulation issues in the hands. In addition, field staff are often simply waiting between sample collection during drilling or excavation activities, further reducing body temperature in both the core and extremities. In order to help mitigate risks, field staff should minimize the amount of time where the hands are exposed during sampling, wear appropriate winter gear and try to keep mobile as much as possible to reduce body heat loss. Take breaks in warm areas such as a heated vehicle or building when needed, and on a schedule if necessary. Additional measures such as warming packets for hands and feet can be utilized to help reduce heat loss in the extremities.
Snow and Ice Accumulation
The accumulation of snow and ice on-Site can present significant issues with the flow of work in the field. Beyond simply making it more difficult to move around, snow and ice visually obscure the ground surface, which often creates issues with locating paint marks identifying underground utilities marked by a locator as well as hiding flush-mount groundwater monitoring wells. The use of site plans, utility plans, GPS units, and even metal detectors can assist in locating items under the snow and ice, but all of these tools have margins of error which can still result in significant on-Site delays. In cases where snow and ice cover is expected, planning ahead is the best option. Have the locator use flags as well as paint if possible to mark utilities. Stake out monitoring wells or identify markers on-Site in relation to wells when they are installed so that they are easier to find when returning to site.
Snow and ice can also present issues with health and safety in the field. Most obviously they can increase the chances of slips, trips, and falls and caution must be used (along with appropriate footwear) when travelling on foot. This is particularly important during excavation programs, as snow can fill in excavations making them appear to be much shallower than they actually are. Care should be taken to never enter excavations that contain snow accumulation. Perhaps the most significant danger when undertaking field work during winter months is the mobilization to the Site. Often the dangers of driving during winter conditions are overlooked. When driving conditions are too hazardous, consider postponing field work, or staying in a hotel close to the Site. While this may result in some minor additional costs, it certainly outweighs potential ramifications if an accident were to happen due to dangerous road conditions.