Sediment Information System W.I.T.©

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1. Contactinformation

Tijhuis Ingenieurs BV

Ir. J.M.H. Tijhuis

Postbus 4084

1620 HB Zwaag

Netherlands

2. Introduction

Tijhuis Engineers is a leading engineering company in the field of regional water

management, specialized in sediments, dredging, GIS and data systems. In addition to

conducting research (in-house measurement teams) and the preparation of maintenance

plans, the company avails of a lot of expertise in the preparation and supervision of dredging.

For planning maintenance operations of drainage systems on the long term, Tijhuis Engineers

developed a sediment information system called W.I.T.©. With this instrument it is possible to

generate long-term dredging plans which efficiently respond to changes in environment,

policies and the market.

W.I.T.© is constructed in a GIS environment and is accessible via the platform Lizard. The

platform is used for the storage, processing and opening up of water-related information

(more information at: www.lizard.net). Several Dutch companies been involved in developing

the open source Lizard platform that is now being deployed in the domestic market as well as

globally in e.g. Nepal, China and Vietnam (figure 1) for projects for water boards and local

and national governments.

Figure 1: Mekong Delta portal, containing various remote sensing images and information.

3. W.I.T.©

The sediment information system W.I.T. © offers an unique combinations of tools which makes

it possible to process data and prepare long-term dredging plans. W.I.T.© is a dynamic web-

based GIS application where all data of the drainage system is stored centrally. Practical

modules allow for the optimisation of maintenance dredging by calculating quantities

dredged material, the testing of data quality and planning of maintenance dredging. The

data can be visualized in tables, diagrams, charts and maps. W.I.T.© provides answers to the

following questions:

Sediment Information System W.I.T.©

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Which waterways should be dredged?

How much material (sediment) to be dredged?

What is the quality (chemical and physical) of the dredged material?

What are the costs of the dredging operations?

Which disposal sites are available?

Design W.I.T. © database

The following geometric database is required:

Hydrological units (representative of culverts and channels). The hydrological units are the

basis of WIT and are stored in a GIS database (shape format). The basic assumption here is

to use -as much as possible- information of already existing GIS databases. Properties (also

known as attributes in terms of GIS) of the hydrological units (such as ID, length,

maintenance profiles, qualities categories etc.) are defined in the database. It’s also

possible to use Google-maps as basic information for the hydrological units.

Uploading data in W.I.T. ©

The fitted databases are filled with data, assumptions and principles:

Cross sections measurements (quantity). Collected data is linked the hydrological units

and corresponding maintenance profiles (figure 2).

Sediment quality (chemical and physical). Assessment results (predefined categories, e.g.

green, orange etc.) are linked to the hydrological units.

Costs. All costs (transport, processing etc.) are converted to costs per m3 sludge or

sediment.

Processing and disposal possibilities and locations.

Planning. Planned years are linked to hydrological units (figure 3).

Additional information. Examples include sediment growth and inventoried obstacles,

cables, pipes, artworks, contractors, etc.

Figure 2: Measured cross section and calculated quantities in maintenance profile

De data listed will be uploaded in user-friendly online WIT interface. Furthermore user

accounts (assign rights) and desired map layers will be created. WIT is web-based, so remote

control and support (e.g. with data uploading by locally trained GIS experts) is possible when

the GIS expert is not present in Dhaka Bangladesh.

Sediment Information System W.I.T.©

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Output WIT: long-term (multi year) dredging plan

The filled W.I.T. © application is then used for the design and planning of dredging

operations. Useful modules calculate quantities of dredged material. Hydrological units can

be clustered and linked to existing schedules (e.g. based on seasons). Eventually, a long term

(multi year) dredging plan is generated which, among other things, an insight gives in

needed budgets.

Figure 3: Using WIT to prepare and generate a long-term dredging plan

Tijhuis Ingenieurs

Hoorn, April 2014