India

India

The hydro-geochemical monitoring network in India consists of a pristine forested catchment, Mule Hole (4.1 km2), and a cultivated catchment, Berambadi (84 km2) with a sub-catchment, Maddur (7.1 km2).

Monitoring set up of the Mule Hole catchment

Check the article published in Hydrological Processes summarizing the M-TROPICS activities in the Mule Hole catchment here.

The monitoring of Mule Hole was initiated in 2003. Classical weather variables (rainfall, temperature, wind velocity and direction, air humidity and global radiation) are monitored with an automated weather station located at the Mule Hole checkpost, one km away from the catchment outlet. The stream water level is measured at the catchment outlet, which is equipped with a weir and an automatic sensor. Groundwater levels are monitored from a network of 9 piezometers. Seven are placed perpendicular to the stream flow at the outlet, and two on hillslope. Geochemical monitoring consists in chemical analysis of daily rainfall events collected manually (intensity > 5 mm), ephemeral stream collected automatically at high frequency (10 to 90 minutes interval) and groundwater collected manually on monthly basis.

Monitoring set up in the Mule Hole catchment

Variables Monitored in the Mule Hole catchment

Variable (unit)FrequencyPrecisionSensor/DeviceYears of use
Weather variablesCimel weather station (ENERCO 407 AVKT)2003-15
Rain (mm)1 hrResolution 0.5 mm, precision 2%
Air temperature (°C)1 hr0.02 °C
Air relative humidity (%)1 hr0.5%
Wind velocity (m/s)1 hr3%
Wind direction (degree)1 hr
Global radiation (W/m2)1 hr0.05%
Weather variablesOTT weather station (WS502 UMB) with Lambrecht rain gauge2015-
Rain (mm)15 minResolution 0.2 mm, precision 2%
Air temperature (°C)15 min±0.2 °C (-20 °C to 50 °C)
Air relative humidity (%)15 min±2%
Wind velocity (m/s)15 min3%
Wind direction (degree)15 min
Global radiation (W/m2)15 min5%
Hydrological variables
Stream level (m)10 min1 mmOTT Thalimedes2003-18
Stream level (m)30 min0.5 cmDiver datalogger (Eijkelkamp)2018-
Groundwater level (m)monthly1 cmmanual (OTT KL 010)2003-
Groundwater level (m)15 min to 1 hr1 mmOTT Thalimedes (2 to 4)2003-15
Groundwater level (m)15 min to 1 hr0.5-2.5 cmDiver datalogger (2 to 3)2015-
Weather and hydrological variables monitored in the Mule Hole catchment

Variable (unit)PrecisionInstrumentYears of use
Electrical conductivity (µS/cm)1%WTW probe (in situ)2003-
pH0.1WTW probe (in situ)2003-
Dissolved organic carbon (mg/L)<5%Shimadzu TOC 50002003-
Alkalinity (µeq/L)10%Manual titration 2003-07
Alkalinity (µeq/L)<5%Mettler Toledo Automatic titrator DL50Gx2007-
Anions F, Cl, NO3, SO4 (µmol/L)<5%Dionex Ion Chromatograph DX6002003-11
Anions F, Cl, NO3, SO4 (µmol/L)<5%Metrohm Ion Chromatograph COMPACT 8612012-
Cations Na, K, Ca, Mg (µmol/L)<5%Jobin-Yvon ICP-OES2003-12
Cations Na, K, Ca, Mg (µmol/L)<5%Methrom Ion Chromatograph COMPACT 8612012-
Silica (µmol/L)10%Hach spectrophotometer DR/24002003-12
Silica (µmol/L)<5%Knauer UV Visible detector 25202013-
Geochemical variables monitored in the Mule Hole catchment

Monitoring set up of the Berambadi catchment

This monitoring was initiated in 2005 in the Maddur sub-catchment (7.1 km2) of Berambadi, and extended to the entire Berambadi in 2010. Weather variables are monitored since 2005 with an automated weather station located at the Maddur checkpost, close to sub-catchment outlet. The Maddur stream water level has been recorded at the catchment outlet from 2005 to 2012 and then from 2019, with a water level automatic recorder similar to that of Mule Hole. Few groundwater levels (through bore wells) were monitored in Maddur from 2006 to 2008 with data loggers. From 2005 to 2012 the Maddur outlet was also equipped with an auto-sampler that collected at high frequency (60 to 90 minutes) the ephemeral stream storms for chemical analysis. The spatial distribution of groundwater chemical composition in the cultivated part of Maddur (half downstream) has been monitored from 2006 to 2011.

Monitoring set up in the Maddur catchment

In Berambadi, an extensive monitoring of groundwater levels (n=200) was initiated across the catchment in January 2010, on monthly basis, from the tube well network used for agriculture. Two tube wells were also equipped in 2016 with data loggers for recording groundwater levels at hourly frequency. The spatial distribution of groundwater chemical composition is determined in Berambadi since 2012, by collecting manually and analysing 140 to 180 tube wells at each campaign. Such density allows to map groundwater level and composition at the catchment scale.

Monitoring set up in the Berambadi catchment

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