Spring cleaning | 1000+ glass bottles | closing the water sampling circle ...

Like squirrels loads and loads of water samples were collected, analyzed and the boxes stored in the basement in case a re-analysis is necessary. Now with the new sampling season starting, already storage places are piling out and all shelf and cupboards are full with 250 and 20 ml bottles from old projects (20-ml glass vial with cap and additional Teflon/rubber septum) and 250 ml for hydrochemical analyses (250-ml PE bottle with cap): Furka, Rietholzbach, Hotzenwald, Reppisch , or see Fischer et al. HP 2015, Fischer et al. HR 2017 or Fischer et al. JOH 2017 (click link for more info).

Storage are piling out ...

Spring time is also cleaning time. In five steps the full "pizza" boxes were emptied into a big box  for transport ( see 1 |  loaded with fully to be discarded sample bottles of 20 ml;  AxBxC =  40x 42x60  cm ). How many  bottles of 15.7 g would be in the box ... (check later on ). In a #$@%$#@ job all caps were removed and disposed (see 2), the water was drained in the sink. All emptied bottles were sorted in a washing rack and submerged into washing basing with deionized water (see 3). The clean bottles were stored in a box, waiting for the drying in a oven at 105 deg C. After drying and cooling down, the clean bottles are packed for storage. Following the five step, 2.5 hours later ... bottles are ready for new water samples and loads of interesting stable isotope data.  Only new caps are needed + lots of taxpayers CHF saved :D

Five steps to clean bottles :) 

In theory also the caps could be recycled by peeling, in a cumbersome way, the rubber septa from the plastic cap. One reason way using new caps can be seen in the pic below. The broken caps were observed in 50 out of 1510±20 bottles and most likely caused by screwing the cap too firmly on the sample bottle. Expansion of the water during the warmer summer period  and plastic fatigue resulted in a failure of the cap (after +6 years of storage). Hence, nice fractionation. So be careful with caps and long time storage!!!!

Broken caps -> fractionation.  

Morning ritual - Evaporation

Unfortunately in most cases we can see water change from liquid to vapor. However, morgenstund hat Gold im Mund, the early bird catches the worm or a hydrologist catches evaporation check the video with a cup of tea evaporating. Check the thin layer of condensation (whitish) on top the tea blown away ...

Have a nice day :)

... +1 <:D update: 24.01.17 | Spatial variability in the isotopic composition of rainfall

Abstract

Isotope hydrograph separation (IHS) is a valuable tool to study runoff generation processes. To perform an IHS, samples of baseflow (pre-event water) and streamflow are taken at the catchment outlet. For rainfall (event water) either a bulk sample is collected or it is sampled sequentially during the event. For small headwater catchment studies, event water samples are usually taken at only one sampling location in or near the catchment because the spatial variability in the isotopic composition of rainfall is assumed to be small. However, few studies have tested this assumption. In this study, we investigated the spatiotemporal variability in the isotopic composition of rainfall and its effects on IHS results using detailed measurements from a small pre-alpine headwater catchment in Switzerland. Rainfall was sampled sequentially at eight locations across the 4.3 km2 Zwäckentobel catchment and stream water was collected in three subcatchments (0.15, 0.23, and 0.70 km2) during ten events. The spatial variability in rainfall amount, average and maximum rainfall intensity and the isotopic composition of rainfall was different for each event. There was no significant relation between the isotopic composition of rainfall and total rainfall amount, rainfall intensity or elevation. For eight of the ten studied events the temporal variability in the isotopic composition of rainfall was larger than the spatial variability in the rainfall isotopic composition. The isotope hydrograph separation results, using only one rain sampler, varied considerably depending on which rain sampler was used to represent the isotopic composition of event water. The calculated minimum pre-event water contributions differed up to 60%. The differences were particularly large for events with a large spatial variability in the isotopic composition of rainfall and a small difference between the event and pre-event water isotopic composition. Our results demonstrate that even in small catchments the spatial variability in the rainfall isotopic composition can be significant and has to be considered for IHS studies. Using data from only one rain sampler can result in significant errors in the estimated pre-event water contributions to streamflow.