Q-hydrology strongly believes in the use of open-source software for its models and tools. This means that most of the software we use is freely available and therefore easily redistributable. Using open-source software has three main benefits for the customer:

1. Q-Hydrology can keep overhead costs low compared to other consultants in the same market, and as such offer competitive prices for our services
2. The customer can view and modify the code (e.g., hydrological model, or operational forecasting application) long after the project has been completed, without any additional cost
3. The open-source community is growing world-wide, meaning that online support is likely easily to be found and freely available, reducing the need for additional consultancy services

Models

Model	Applications
Spatial Processes in HYdrology (SPHY)	River flow Soil moisture Groundwater recharge Snow and glacier processes Climate change impact assessment
HEC-HMS	River flow Scenario analysis Climate change impact assessment River basin management
	River flow Groundwater recharge Adaptation strategies Scenario analysis River basin management
Soil Water Atmosphere Plant	Soil moisture Groundwater recharge Crop yield Irrigation water requirements Drainage Scenario analysis
Water Evaluation And Planning	Water allocation Adaptation strategies Scenario analysis River basin management
SUTRA A Model for 2D or 3D Saturated-Unsaturated, Variable-Density Ground-Water Flow With Solute or Energy Transport	Unsaturated flow Saturated flow Variable-density groundwater flow Solute transport

Tools

Python

Q-Hydrology has extensive experience in using Python. Python is a powerful programming language that is used in the scientific community world-wide. It is open source, making it freely usable and distributable. We use Python for a wealth of tasks, including model and tool building, data processing and analysis, data visualisation, and developing operational services.

An overview of some of our models and models that are developed using Python can be found on our GitHub repository.

PCRaster

PCRaster is an environmental modelling framework targeted at the development and deployment of spatio-temporal environmental models and was developed by Utrecht University, the Netherlands. Q-Hydrology has extensive experience in using PCRaster for its modelling applications. Some examples are its implementation in the Spatial Processes in HYdrology (SPHY) model, and its use in an operational spatially distributed soil moisture model for the Netherlands. PCRaster is open source and therefore freely usable and distributable. Because PCRaster is built in C++, models created in PCRaster execute extremely fast. Python can be used to control PCRaster, making it the perfect tool for developing operational services and applications.