Читать книгу Fieldwork Ready - Sara E. Vero - Страница 23

Event sampling is perhaps most common in hydrology and related fields. This approach involves taking samples during or subsequent to specific target conditions. This frequently involves measurement of surface water quality in response to storms, which generate overland flow and runoff of potential contaminants such as sediment or pesticides to surface water, although subsurface leaching and preferential flow may also be triggered under such conditions. Event sampling will involve fairly typical techniques; the key difference is in preparedness and timing. As events can be both sudden and relatively brief, if you are not completely prepared in advance you may miss them. There are some steps which can help:

 You can set email or text alerts either linked to weather stations or dataloggers at your site or linked to meteorological forecasts from reliable sources.

 Have a grab‐bag of tools and equipment so that you can deploy to the field at short notice.

 Know how long it takes for you to safely get to your site, and how long you need to conduct your sampling. Your alert must be far enough in advance to allow you to get there. If it takes 36 h to reach your site, for example, a 24‐h weather warning will be of no use as it will be impossible for you to reach the site in time to capture the event.

 Keep your vehicle fueled.

 If your site is distant or if you have a good general estimate of when a future event might occur (e.g., which month typically receives most storms), consider deploying to the field or to a nearby location in advance. It may be more effective to stay at a hotel near the location and limit the risk of missing the event.

 Be safe! Event sampling may pose elevated risks for several reasons that should be considered when preparing your hazard and risk assessment:Weather might be cold, wet, and windy, making driving conditions poor.Stream or river discharge will be high, elevating the risk of being washed away, drowning, and slips or trips.You might feel rushed and take more risks, be less thorough, and feel more stressed or distracted.