Setting up a new CZO in the Ganga basin: instrumentation, stakeholder
engagement and preliminary observations
Abstract
The Ganga plains represent the abode of more than 400 million people and
a region of severe anthropogenic disturbance to natural processes.
Changing agricultural practices, inefficient use of water, contamination
of groundwater systems, and decrease in soil fertility are some of the
issues that have affected the long-term resilience of hydrological
processes. The quantification of these processes demands a network of
hydro-meteorological instrumentation, low-cost sensors, continuous
engagement of stakeholders and real time data transmission at a fine
interval. We have therefore set up a Critical Zone Observatory (CZO) in
a small watershed (21 square Km ) that forms an intensively managed
rural landscape consisting of 92% of agricultural land in the Pandu
River Basin (a small tributary of the Ganga River). Apart from setting
up a hydrometeorological observatory, the major science questions we
want to address relate to development of water balance model,
understanding the soil-water interaction and estimation of nutrient
fluxes in the watershed. This observatory currently has various types of
sensors that are divided into three categories: (a) spatially not dense
but temporally fine data, (b) spatially dense but temporally not fine
data and(c) spatially dense and temporally fine data. The first category
represent high cost sensors namely automatic weather stations that are
deployed at two locations and provide data at 15 minute interval. The
second category includes portable soil moisture, discharge and
groundwater level at weekly/ biweekly interval. The third category
comprises low-cost sensors including automatic surface and groundwater
level sensors installed on open wells to monitor the continuous
fluctuation of water level at every 15 minutes. In addition to involving
the local communities in data collection (e.g. manual rainfall
measurement, water and soil sampling), this CZO also aims to provide
relevant information to them for improving their sustainability. The
preliminary results show significant heterogeneity in soil type,
cropping system, fertilizer application, water quality, irrigation
source etc. within a small catchment.