Wybrand van Ellen Aguaflow S.L. (AGUAFLOW) is an independent geohydrological consultancy that offers solutions to a wide range of groundwater related problems at home and abroad.

Since 2002, AGUAFLOW Ltd. has been located in Spain. Our expertise, however, has mainly been gained in the Netherlands from 1989 on, and more specifically at WL | Delft Hydraulics (currently part of Deltares). In addition to working in the Netherlands and Spain, we have work experience in other countries such as the Bahamas, Bahrain, Belgium, France, Indonesia, Portugal, Mozambique and Somaliland

We can realize our projects in either Dutch, Spanish, or  English. This capability is advantageous for those Dutch and English companies that wish to operate within the Spanish water market.

Business Approach
Every project is unique and is treated as such by AGUAFLOW. We aim to provide our clients with bespoke solutions to each challenge. So that we may achieve this goal we always decide -in close contact with our client- on a specific approach at the initial phase of a project.
This method is based upon our expertise and many years of experience, complemented by the most sophisticated geohydrological modelling.

If required, AGUAFLOW can offer clients the added value of a close cooperation and shared expertise with two other international companies: AQUACONSEIL Belgium (experts in groundwater) and SIEBE BOSCH HYDROCONSULT Holland (surface water).

In this way, we are able to ensure complete client satisfaction and deliver a clear solution to the brief within the designated timescale.



From 1989 we have been active on these fields of action:

In addition to these technical projects AGUAFLOW also executed the following, more general, studies:


Modelling expertise

For the majority of our geohydrological projects we use one or more of the modules of the software package VISUAL MODFLOW. We have applied these modules in both stationary and transient situations

MODFLOW for the calculation of 3D-groundwater flow
MODPATH for the calculation of 3D-pathlines using results from MODFLOW

for the calculation of water balance of subsystems within the model area

SEAWAT for the calculation of density-dependent flow
MT3D for the calculation of the 3D-transport by advection, dispersion, and chemical reactions of dissolved constituents
RT3D for the calculation of 3D-multi-species, reactive transport

Furthermore, we have the following programs at our disposal:

SUPER SLUG for pumping tests analysis
SURFER for data processing and analysis

We also have knowledge of the groundwater models TRIWACO and MICROFEM, the SOBEK software package and programs to make and process photographs and professional images.



Hargeisa (Somaliland)

Review of the existing stationary, 2D-model of the aquifer north of the capital Hargeisa. The aquifer forms the only source for the water supply of Hargeisa. In the next phase, once new data become available, the model will be modified (transient, 3D), extended in order to take into account neighbouring aquifers and updated.
Determination of the best locations for new wells in order to meet future water demands.
Client: UN-Habitat


Maputo (Mozambique)

mozambiqueReview of the existing stationary, 2D-model of the aquifer around Maputo and next, extension of the model in order to obtain a transient 3D model that takes into account density-driven groundwater flow.  The model will help the National Water Directorate in sustainably managing the aquifer. The aquifer will contribute to the water supply of Maputo.
Client: Water board  ARA-Sul




Almería (Spain)

Development of a groundwater model, calibrated for the period 1980 – 2008, of the groundwater flow in the region of El Ejido, a zone of intensive agriculture. Besides, determination of appropriate locations for groundwater withdrawal in order to spare zones that are under the threat of salt water intrusions.

In a follow-up study, we determined the effects on the groundwater heads of the reduction of the water level in the “Balsa del Sapo”, a lake fed by draining groundwater. This reduction took place by the construction of a drain from the Balsa del Sapo to the Mediterranean Sea.
Client: Zofre SLP

el ejido



Client: Hoogheemraadschap van Rijnland (Rijnland Waterboard)


Tatakoto (French Polynesia)
Support of Ginger Environnement & Infrastructures in developing a groundwater model of the atol Tatakoto in order to determine the subsurface transport of potential leakage of contaminants from a planned/projected landfill. The concentration course at the settlement of Tumukuru was assessed as well.
The groundwater flow is steered mainly by the tide and the resulting density-dependent flow in the very permeable soil of the atol.



Development of a geohydrological model of the city of Barcelona between the rivers Llobregat and Besós (approximately 235 km2). Transient calibration was based on observed heads for the period 2003 – 2005.
Objective: Determination of the impact on groundwater flow of a tunnel for the trajectory Sants – La Sagrera of the High Speed Train Madrid – Zaragoza – Barcelona – French border



Development of a geohydrological model of the lower Jalón catchment (approximately 1,000 km2). Transient calibration was based on observed heads for the period 1989 – 2006.
Objective: Delivery of an instrument that enables the “water board” (Confederación Hidrográfica del Ebro, CHE) to study the behaviour of the geohydrological system. Imperative was the impact of the groundwater withdrawals (taking place since the 70´s) on the decline of the Jalón discharge. The CHE will use the model as a regional management tool: before a withdrawal permission is granted, the impact of the new withdrawal will be calculated.



Development of a geohydrological model of the aquifer beneath the river Ebro in the surroundings of Zaragoza (approximately 600 km2). Transient calibration was based on observed heads for the period 1997 – 2001.
Objective: the main objective was to offer support in the application of the Water Framework Directive (WFD) in Spain in a pilot project. This pilot project, in which the model formed an important tool, aimed at the additional description of the alluvial aquifer of the Ebro. The water quality in the aquifer is under great stress because of intensive industrial activities. As a consequence, the aquifer runs the risk of not meeting the water quality requirements as given in article 4 of the WFD. The model provides insight into the spreading of the contaminants.



Soil remediation projects
These include small-scale projects (< 1 km2), aimed at determining the extents of a contamination (in particular with BTEX, PCE, TCE, DCE and VC) and consequently designing remediation options and determining their effectiveness. Processes considered in the hydrochemical simulations are, amongst others, sorption-desorption behaviour of the aquifer, half-life of the contaminant, dispersion and advection.

soil remediation


Pumping tests analyses
For these projects the permeability of the soil is determined on the basis of the results of pumping tests (time/groundwater heads graphs).



TECHNEAU-climate study
Execution of the case study Spain in the framework of the EU-project TECHNEAU. TECHNEAU, a project funded by the European Commission, studies both the capacity of traditional drinking-water supply and the technical solutions to guarantee future supply in view of current and future possibilities and threats.
In the case study, an inventory was made of the way Spain anticipates the expected climate change in the fields of drinking water production and –supply. The AGUAFLOW-reports can be opened or downloaded by simply clicking on the figures.


Sludge deposit studies
Development of groundwater models for the calculation of the spreading of contaminants from sludge deposits.
Objective: to determine whether or not the emission standards for the substances lixiviated (PAH´s, PCB´s and heavy metals) are exceeded.

sludge deposit


Inventory Spanish freshwater market
Inventory of the Spanish freshwater market on the level of Confederaciones Hidrográficas (equivalent to water boards). Per catchment a description of the (hydrological) problems, the selected solutions and the use of hydrological models was given. In order to be able to place this regional problems and solutions in a wider context, the National Hydrological Plan and the White book of Water were studied.







Dutch English
Aquaconseil International Association of Hydrogeologists
Siebe Bosch Hydroconsult The Hydrogeologist
Nederlandse Hydrologische Vereniging
(Dutch Hydrological Society)
Waterforum Environmental Health Safety Freeware

Hydrologische woordenlijst
(Hydrologic vocabulary)

United States Geological Survey (Water)


Fundación Nueva Cultura del Agua
(Foundation New Water Culture)
Ministerio de Medio Ambiente y
Medio Rural y Marino (Agua)
(Ministry of Natural, Rural and
Marine (Water) Environment)
Asociación Española de Hidrogeólogos
(Spanish Hydrogeological Society)



Wybrand van Ellen AGUAFLOW S.L. tel: +34-978710173
Camino de la Vega 2 gsm: +34-635628718
44100 Albarracín fax: +34-978710138