Recent research — Talla Earth Observatory

In 2008–09 the area of the Observatory was extended to reach the eastern shore of the Talla Reservoir.

two specialists near monitoring equimpent     specialist checking monitoring equipment

Research has focused on the initiation of time series monitoring of environmental changes in the enlarged observatory area:

  • monitoring stability of active talus covered slopes and the accumulation of active alluvial fans using Terrestrial LiDAR scanning and dGPS grids of slope movement markers
  • daily measurements of shallow groundwater movements and temperature in two boreholes (groundwater monitoring and modelling)
  • hourly weather records from an automated weather station

Aims

A principal aim of this monitoring is to establish an integrated model of the shallow Water Cycle within the Talla Water catchment, by linking precipitation to groundwater movement and eventually to surface run off and stream recharge and discharge. To this end a future programme of nested stream gauging is planned.

diagram of precipitation at Talla

Borehole data

Data from the groundwater levels in the two instrumented boreholes is already showing the lag in time between groundwater recharge to the alluvial gravels and recharge of the surrounding glagicenic sediments. Integration of the precipitation data from the weather station will allow the lag between precipitation and groundwater movement to be established.

The weather record will also enable the recognition of high intensity storm events, and establish if these are increasing in frequency with future climate change. These localised storms also trigger slope instability. Long-term monitoring of both talus slopes and fan aggradation should quantify the responses of these active landscape elements to changing climatic conditions.

An automated ISCO Water Sampler will be installed on the Talla Water in 2010. This unit will be calibrated to trigger sampling during peak stream discharges. It will establish changes in suspended sediment load, and dissolved carbon at high flow rates. The latter will provide quantifiable data on the impact of increased storminess on carbon storage in upland peats and organic soils. The weather station data will also be used to model soil moisture changes in the catchment. These will be calibrated by Gulph permeameter measurements of soil permeability (taken in November 2009) and compared with the detailed 4500 year proxy record of peat surface wetness at Talla Moss derived from peat cores.