This CZO is located in a small watershed (21 km2; 80°8’0”E-80°11’0”E and 26°31’43.93”N- 26°36’14.85”N) of the Pandu river basin, a tributary of the Ganga River. It was established in August 2016 with support from the Ministry of Earth Sciences, Government of India and is being monitored by Indian Institute of Technology Kanpur. It is the first CZO in the Ganga Basin, and second in the country after the Kabini CZO in Karnataka. The major objective of the new observatory is to monitor various climatic, hydrological and geochemical parameters related to the critical zone and to understand physiochemical processes responsible for its sustenance. The new CZO adds to the existing network of global CZOs and provides a platform to the scientific community to predict and address foreseeable challenges in food security and clean water availability in one of the most densely populated regions in the world.
The watershed for setting up this CZO was chosen such that it is representative of the agricultural land use in the intensively managed rural parts of the Central Ganga alluvial plain in Uttar Pradesh. The elevation of the watershed ranges from 126 m to 143 m above MSL. The study area has a sub-humid climate and is characterized by two soil types, sandy loam, and loam. The average annual maximum and minimum temperatures are 42°C and 8.6°C respectively, and the average annual rainfall is 821.9 mm majorly occurring in June-September. The major land use/land cover (LULC) types, established using unmanned aerial vehicle (UAV) data, are - Cropland 92 %, Built up area 3.6 %, Barren land 2.6% and Waterbodies 1.2%.
An array of sensors has been deployed in the watershed for continuous monitoring of hydro-agro-climatic variables. These monitoring networks are divided into three categories on the basis of the spatial and temporal resolution of the measured data:
(1) Spatially sparse but temporally fine data: Two automatic weather stations measuring meteorological variables (solar radiation, rainfall, temperature, humidity, wind speed and direction, atmospheric pressure, pan evaporation, and soil moisture, temperature and heat flux) at 15-minute intervals.
(2) Spatially sparse and temporally coarse data: Portable but expensive instruments, which are used for weekly or bi-weekly measurements of surface soil moisture, leaf area index, groundwater level in open wells, pond water levels, and discharge in the mainstream during monsoon.
(3) Spatially dense and temporally fine data: low-cost sensors developed in-house that use low-power wide area network (LPWAN) technology for real-time communication. They are presently being used to collect groundwater, canal water, and pond water levels.
In addition, we have collected data on static variables like topography, soil type and LULC by remote sensing using a drone at a high spatial resolution of 20 cm. Data on agricultural and irrigation practices are periodically collected using farm surveys and mobile crowdsourcing.
The CZO in the Ganga basin provides an opportunity to establish an understanding of how anthropogenic activities are shaping today’s environmental processes in the IGP and how they may respond to future changes. Currently, the observed data are intended for water balance modeling, crop water management, and water quality mapping. The outcomes will be shared with the stakeholders’ community to mitigate water mismanagement and further soil quality degradation. The CZO will ultimately provide scientific evidence and decision support tools that will help to shape policy and management options to meet today’s needs and to sustain the natural capital of the Ganga critical zone for future generations.