What is hydrology?

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Hydrology is the scientific study of water in all its forms and its interaction with the Earth and its atmosphere. This complex discipline seeks to understand water’s properties, movement, distribution and impact.

Hydrology examines every phase of the water cycle, covering everything from rainfall and surface runoff and its eventual return to the atmosphere to groundwater seepage and even returns to the surface.

Specifically:

  • Surface hydrology focuses on water that flows over land, determining how rainfall translates to runoff and travels through built environments as well as through streams, lakes and rivers.
  • Hydrogeology explores groundwater systems, analysing how water moves below the earth’s surface through soil and rock.

Understanding these processes, including the interactions between surface water and groundwater, is essential for effectively managing water resources, mitigating natural disasters and adapting to environmental changes.

However, at GHD, we understand hydrology and hydrogeology in a different dimension. Engineering hydrology and hydrogeology focuses on assessments, such as:

  • Flood or drainage modelling
  • Yield analysis
  • Dewatering assessments
  • Water resources management
  • Aquatic habitat conservation
  • Stormwater management
  • Water balances supporting project development and design

Why hydrology and hydrogeology matters

Climate change’s impact in shifting water patterns, such as flooding, drought and other extreme weather events, compounded by population growth and increasing urbanisation, are challenging water infrastructure in water sanitation, energy production and industrial use, among others.

Engineering hydrology and hydrogeology helps us learn about water’s role in shaping our world and how we can use it wisely to support both human and natural needs. It also equips us with the knowledge and tools needed to overcome these challenges. By uncovering water’s patterns and behaviours, we can create solutions that cater to both human need and ecological sustainability.

What is GHD doing about it?

As a global professional services company, GHD applies hydrology and hydrogeology assessments to projects across our offerings in the water, energy and resources, environment, property and buildings, and transportation markets.

Hydrology and hydrogeology are woven into nearly every service we offer. Whether it’s mitigating risks, optimising water use or adapting to environmental shifts, our specialists combine scientific knowledge with engineering capability to tackle surface and groundwater-related challenges across industries.

Here’s how we support clients globally:

Surface water and flood risk management

GHD works to understand and reduce flood risks for infrastructure and communities. For example, in Halifax, Canada, we updated floodplain maps using historical data and advanced hydraulic modelling, helping the city better prepare for climate-related challenges.

Sustainable urban water design
By capturing and treating urban runoff, this approach can help improve water reuse while minimising environmental impact.
Aquifer Storage and Recovery (ASR) scheme

The ASR scheme utilises Class A treated recycled water. It’s injected into the aquifer system during periods of excess water/low demand periods and extracted during high demand periods.

Critical infrastructure resilience
GHD’s deep toolkit can support energy projects, such as solar and wind farms, with hydrology and hydrogeology assessments for approvals and flood risk management during construction.
Groundwater production wells

GHD’s hydrogeologists identify and assess groundwater sources to help communities establish sustainable water supplies. They manage all aspects of groundwater development, including exploration, well design for diverse settings and uses, testing, commissioning, maintenance and decommissioning.

Integrated surface water and ground water modelling
When downstream water quality and ecosystems were impacted by groundwater abstraction and climate-induced drying activated acid sulphate soils in a natural swamp environment, a hydraulic barrier remediation system was proposed to redistribute flow and maintain water levels. GHD was engaged to deliver integrated surface water–groundwater modelling to simulate seasonal wetting and drying dynamics, flood flows, shallow groundwater interactions and baseflow responses to inform the detailed design of the system.

Hydrology and hydrogeology are integral to understanding and addressing the complexities of water management in a changing world. At GHD, we apply our knowledge to help manage water responsibly, balancing human needs with environmental sustainability. From reducing flood risks to enhancing urban water systems and supporting resilient infrastructure, we focus on solutions that deliver long-term benefits for communities and ecosystems.

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Want to go deeper?

To learn how GHD applies hydrology practices to manage water responsibly and support resilient infrastructure, explore our services.
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