SDT Division



Md.Tarikul Islam
Director
Survey & Data Division

Survey & Data Division (SDT) 

Survey data of good quality is vital for the design, planning, implementation, and maintenance of infrastructure development, especially in the field of water resources management. Considering the importance of quality data, IWM maintains its Survey and Data Division which is enriched with all types of sophisticated modern survey equipment in addition to conventional equipment in the field of topographic, hydrographic, ocean, sediment sampling and water quality measurement. The present-day state-of-the-art survey equipment has come up to provide additional advantages to make the field survey faster and more comprehensive. These types of equipment have sophisticated electronic circuits with memory and other gadgets. The operation and maintenance of these types of equipment require specialised skills. IWM has been maintaining a substantial stock of field survey equipment along with well-trained survey experts and engineers since 1996. The eventual procurement of highly specialized equipment like Multibeam Echosounder, Terrestrial Laser Scanner, RTK-GPS, UAV and Acoustic Doppler Current Profiler has enriched IWM’s surveying capacity to a level unmatched by others. This division also has its survey vessels for uninterrupted hydrographic surveying. This division is capable of almost all types of survey assignments practiced worldwide. Nonetheless, some of the conventional equipment like Auto Level, Total Station and Conventional Current Meters are still in use for works where those are still suited.  

Hydro-meteorological Measurements (HMM) 

Hydro-meteorological data is essential for the planning, design and implementation of all water-related projects including irrigation, drainage, and flood control. IWM collects Hydro-meteorological data by maintaining the quality through frequent supervision of the collection system in the field as well as systematic processing and consistency check of the data in the office.

  • Water Level
  • Liquid flow
  • Sediment volume and fall velocity
  • Rainfall
  • Temperature
  • Pressure
  • Groundwater
 

Hydrographic Survey (HgS) 

IWM has proven experience in collecting the following types of data to support morphological assessment of the rivers for bank protection and drainage improvement.

  • Bathymetry / Cross sections of the rivers
  • Bank line movement
  • In-situ measurement of floodplain sedimentation
  • WL and flow velocity
  • Wave measurement
 

Multibeam and Single Beam Survey 

IWM maintains both Multibeam and Single-beam systems for hydrographic surveys. Multibeam Echosounder System is used for bathymetric surveys where total coverage of the seabed is required. IWM has acquired 2 sets of Multibeam Systems for survey works namely Teledyne Reason (Model T20R) and Teledyne Odom (Model MB2). Model T20R is capable of measuring river/seabed using 512 beams and up to 165-degree swath width. The output of T20R has high-resolution data and minimum noise. Model MB2 is also a precision instrument capable of measuring river/seabed using 512 beams and up to 140-degree swath width. The instrument is suitable for use in ports & harbour, dredging monitoring, river training works monitoring, monitoring scour holes around bridge piers and river training work. 

Current & Wave Measurement 

IWM measures current and waves in the river and estuaries with two 2 different types of ADCP. For inland rivers, moving boat measurement is done by mounting the ADCP on a boat. Models used in IWM are Workhorse Sentinel 600 KHz and River Ray 600 KHz. For estuary and tidal areas where continuous time series current data at a fixed location is needed, fixed or stationary deployment is necessary. IWM owns 3 Sentinel V ADCPs that can be used for such measurement. This equipment can be mounted on the boat for shorter deployment and where only current data is required. For long-time data collection, the ADCP is deployed in the seabed on specially built mounting with the help of the Diving Team. It has an internal battery and data is stored directly inside the ADCP. 

Topographic Survey and Mapping (TSM) 

IWM measures current and waves in the river and estuaries with two 2 different types of ADCP. For inland rivers, moving boat measurement is done by mounting the ADCP on a boat. Models used in IWM are Workhorse Sentinel 600 KHz and River Ray 600 KHz. For estuary and tidal areas where continuous time series current data at a fixed location is needed, fixed or stationary deployment is necessary. IWM owns 3 Sentinel V ADCPs that can be used for such measurement. This equipment can be mounted on the boat for shorter deployment and where only current data is required. For long-time data collection, the ADCP is deployed in the seabed on specially built mounting with the help of the Diving Team. It has an internal battery and data is stored directly inside the ADCP. 

Laboratory Analysis of Sediment Samples (Sediment Lab)

IWM maintains a well-equipped sediment laboratory to analyze the sediment samples to support morphological assessment of the rivers. The services provided by the sediment laboratory include:

  • Grain size distribution of the bed materials
  • Concentration test of suspended sediment
  • Separation of fine and coarse sediment in suspension
  • Grain size distribution of suspended sediment.
 

Water Quality Investigation (WQI) 

Understanding of the level of water quality parameters is essential for the conservation of environment including drinking, irrigation, fisheries and recreation. During recent days IWM has acquired sufficient skill in monitoring the following water quality parameter for different studies.

  • Salinity, pH, Electrical Conductivity
  • Total Dissolve Solids (TDS), Total Suspended Solids (TSS)
  • Biochemical Oxygen Demand (BOD)
  • Chemical Oxygen Demand (COD)
  • Dissolved Oxygen (DO)
  • Calcium (Ca), Magnesium (Mg), Sodium (Na), Potassium (K), Fluoride (F)
  • Chlorine (Cl), Chloride, Bromine (Br), Sulfate (SO4), Orthophosphate
  • Alkalinity
  • Hardness, Total
  • Iron (Fe)
  • Manganese (Mn)
  • Ammonia (NH3), Nitrate (NO3)
  • Color, True and Apparent, Lead (Pb), Chromium (Cr)
  • Zinc (Zn)
  • Phosphate (PO4)
  • Coliforms
  • Turbidity