Groundwater

Introduction

Land subsidence is a global phenomenon and is defined as:

“a gradual settling or sudden sinking of the Earth's surface due to removal or displacement of subsurface earth materials”  - National Oceanic and Atmospheric Administration (2021)

The challenge

Water is one of the most important substances on Earth and covers 70% of the planet. However, freshwater makes up a very small fraction with 97% being saline and ocean-based. While the amount of freshwater on the planet has remained fairly constant over time, the world’s population has exploded, meaning that freshwater is threatened by significant forces, like overdevelopment, polluted runoff, and global warming. 

Local perspectives and case studies

The aim of the local perspectives and case studies feature is to learn about gaps in water resource management from affected individuals, communities, civil society, professionals, researchers or organisations in the field to identify needs or potential solutions that space technologies could contribute to.

The Human Right to water and sanitation

What does your morning routine look like? For most readers I’d assume you use the toilet, wash your hands, and maybe take a shower.  However, do you ever stop to consider the water you use to shower, or the soap you use to wash your hands? Often, especially in developed countries, these things are taken for granted, rightly considering access to adequate water, sanitation, and hygiene (WASH) as basic Human Rights (Figure 1).

Global groundwater supplies

Groundwater accounts for 30% of Earth’s freshwater resources (Shiklomanov 1993) (Figure 1) and is estimated to globally provide 36% of potable water, 42% of irrigation water, and 24% of industrial water – indicating its significant value (Global Environment Facility 2021). Groundwater affords a host of benefits, from providing better protection against drought and microbiological contamination than surface waters, to being generally low cost and accessible to many users.

Continuous and reliable global precipitation information is crucial for myriad of weather, climate and hydrological applications. The importance of precipitation in the form of rain, hail, sleet, snow etc. is known to science and clear to a layman. However, it’s quite tricky to measure past precipitation trends or predicting accurate future forecasts. There are three main categories of precipitation data sets available: ground based, satellite-based and blended products of ground and space data (Climate Data Guide, 2014).