Data from 2009

Our embedded sensor networks were designed to continuously monitor water levels, bulk ionic solutes and temperature at time scales of 15 to 30 minutes. Hydrologic data from initial deployments in Crystal Bog and Trout Bog are displayed graphically below. In the future, investigators will be able to link to near-real time data from any location with Internet access. The addition of organic carbon sensors is also anticipated.

Crystal Bog.

2008. Data collected during August and September show that the embedded sensors can detect small changes water level in response to even a few millimeters of rain (Fig. 1). For this time series, the response in the CB pond and peatland was directly proportional to the amount of antecedent rainfall. However, the peatland water table rose by almost two centimeters for each centimeter of rain due to displacement by peat solids (Fig. 2).

Figure 1. Water flux data from the second generation MOTE network in Crystal Bog, late summer 2008. Data collected from each sensor at 15 minute intervals

Figure 2. Response of water levels in the CB pond and peatland to precipitation events of various sizes. Note that the response of the lake was 1:1; but the peatland water table responded more strongly to any given event (2:1).

2009. Hydrologic data from the wireless sensor network at Crystal Bog during 2009 are shown on Fig. 3. For this deployment, the sensors logged data at 15 minute intervals.

Figure 3. Hydrologic data from CB pond and associated wetland.

As observed in 2008, the CB pond and wetland water table responded rapidly to rainfall events and declined during dry spells. For most of the monitoring period, the CB pond was perched above the wetland water table. However, during October, the wetland water table rose above the elevation of CB pond.

Comparison with data from the in situ evaporation pan indicate that the loss of water from the CB pond during summer was largely attributable to evaporation (Figure 4).

Figure 4. Comparison of water level changes in CB pond and evaporation pan.

Trout Bog.
2009. Hydrologic data from the embedded INW sensors in Trout Bog during 2009 are shown on Figure 5. The sensors logged data at 30 minute time intervals.

Figure 5. Hydrologic data for Trout Bog during 2009

As observed in Crystal Bog, the TB pond and wetland water table both responded rapidly to rainfall events and to intervening periods of dry-out. As the season progressed, the relative hydrologic gradient between the pond and the surrounding peatland changed – indicating that the flux of water and solutes between peat and pond varied with the antecedent weather.