Flood Control and Drainage Improvement: Emphasised methods and frameworks 

to control floods and improve drainage, guaranteeing sustainable water flow and 

reducing damage under severe weather conditions.

Coastal and riverbank erosion management: It is the process of stabilizing and 

preventing erosion brought on by both natural and man-made factors.

Measures for navigation enhancement: Interventions that make waterways safer 

and more effective for navigation, such dredging and waterway mapping, are included 

in the measures for navigation enhancement.

Facilitation of Port and Inland Water Transport (IWT): aimed at creating and 

strengthening port infrastructure and inland water transportation networks to 

boost connectivity and trade.

Irrigation System: Addresses the planning and development of irrigation systems

designed to help in the management of water resources and agricultural operations.

Road Infrastructures & Building Structures: The design and construction of roads,

bridges and buildings to support infrastructure development is referred to as road

infrastructures and building structures.

Components of an Irrigation System The following essential elements are part 

of the Irrigation System and are all necessary for effective water management 

and distribution:

1.Dyke:  A dyke is an embankment or barrier that is built to restrict water flow 

for irrigation or to avoid flooding.

2. The Canal systems: (Main, Secondary, Tertiary, and Minor): The main route that 

transports water from its source, such as a river or reservoir, is called the "Main Canal."

A secondary canal is a branch of the main canal that supplies water to particular areas.

A tertiary canal is a branch of the secondary canal that supplies water to particular areas.

Small-scale canals for accurate water supply to specified plots are known as "Minor Canals."

Figure: Irrigation Canal

3.Check Structures: Structures constructed over ditches or canals to regulate water levels, lower flow rates, and stop erosion.

Figure: Check structure in main Irrigation ditch (Los Lunas)

4.Offtake regulator: A device that controls and regulates the flow of water into fields or from one canal to another is called an offtake regulator.

5. Aqueducts and Syphons: Structures that let water pass beneath obstructions like dykes or roadways. Elevated constructions known as aqueducts are used to transport water  across roadways, valleys, and other obstacles.

6. RCC (Reinforced Cement Concrete) and CC (Cement Concrete) Lining: Lining canals with concrete to ensure effective water flow, improve durability, and stop seepage.

7.Turnouts: Turnouts are the locations where water is redirected into smaller channels or fields from the main or subsidiary canal.

8. Pump House: In areas where gravity flow is inadequate, facilities with pumps to elevate or pressurize water are known as "pump houses."

Designing an irrigation system involves carefulness to guarantee effective water distribution to crops while preserving resources. We consider and focus on every agronomic and environmental factor while building the layout, choosing appropriate technologies, and evaluating requirements for an irrigation system. An irrigation system designing requires perfection to the core. It consists of designing the canals, dykes, check structures, regulators, syphon, aqueducts etc. Collaborating with IGW division, DGN unit worked in BIP (Barishal Irrigation Project), KIP (Kurigram Irrigation Project), PIRDP (Pabna Irrigation and Rural Development project) projects.

Components of Flood Management and Drainage Improvement
In order to safeguard infrastructure, agriculture, and human populations, flood management and drainage enhancement systems work to reduce the danger of flooding, control water flow, and provide adequate drainage. The essential elements of these systems are as follows:
1. Levees, dykes, and embankments
• Definition: Elevated constructions along rivers or coastlines that are composed of concrete, earth, or other materials.
• Goal: Limit excessive water levels in the river or other body of water during peak flows to avoid floods.

2. Weirs, flood gates, sluice gates, and regulators
• Regulators: Manage water flow in rivers or irrigation canals.
Sluice gates are mechanically driven gates that regulate water levels and outflow.

Flood gates are constructions that regulate floodwaters and stop them from flowing backward into protected zones.

Engineered systems known as flood control structures are intended to lower the danger of flooding and shield ecosystems, infrastructure, and communities from flood damage. Levees, embankments, flood barriers, and spillways are some of the structures that assist regulate water flow and stop overflow in places that are susceptible. Furthermore, floodgates, retention basins, and diversion channels control surplus water by securely rerouting it during peak occurrences. By providing these solutions, flood management structures can protect areas from the effects of storm surges, river overflow, and excessive rainfall while promoting environmentally friendly practices and sustainable water resource management.

Embankments:

An embankment is a raised structure made of earth or stones that serves a variety of purposes. With the collaboration with CPI Division of IWM and BWDB as the client, a design for Embankment & Protection Work around Dacope Upazila was provided for the Feasibility Study for Restoration and Development of Water Resources Management System of Polder 31 under Dacope Upazila in Khulna District. Same was proposed around Kutubdia Island (Polder-71) and around Matarbari Island (Polder-70) around Sandwip Island. A typical design section for embankment construction as a flood management structure is given below.

Dams:
Multi-purpose dams are a structural measure used to control flooding. A dam is walled construction, known as the water retention structure, keeps water out while permitting a certain amount to flow downstream. Depending on their intended use, the topography, and the resources available for building, they are made of different materials and designs. With the collaboration with FRM Division of IWM and BWDB as the client, Design for Earthen dams were proposed to be constructed in Govania, Ambaria, Kumira and Joramtol under the project of Feasibility Study for Conservation and Use of Rainwater Through Construction of Environment Friendly Water Reservoir at Khoia Chhara and Govania Chhara of Mirsharai Upazila and Kumira Chhara of Sitakunda Upazila Under Chattogram District.

A design for an earthen dam along with spillway, intake tower and pedestrian bridge at  Govania Chhara in Mirsharai Upazila was provided for the Chattagram District's Feasibility Study for Conservation and Use of Rainwater in collaboration with the FRM Division of IWM and BWDB as the client. The same idea was submitted for Sitakunda Upazila's Joramtol Khal and Kumira Chhara. A cross dam was also proposed on the Govania Chhara Reservior, An earthen dam, also known as an earthfill dam, is a kind of dam that is mostly made of natural materials like rock, gravel, sand, clay, or soil. Since building materials are readily available and construction methods are generally straightforward, earthen dams are among the oldest and most popular types of dams. It blends well with the natural landscape. The proposed earthen dams in those areas will retain water, guarantee a consistent supply, and enable precise control over water discharge, guaranteeing effective distribution to industries, municipalities, and irrigation systems.

Components of River Management
Various structural and non-structural measures are used in river management to control sediment movement, reduce erosion, improve navigation, and regulate river flow. The elements of river management are as follows:
1.Revetments Sloped constructions, such as blocks of concrete, rocks, or other materials, are positioned along riverbanks to prevent erosion brought on by water movement. The goal is to stabilize riverbanks and lower the chance of collapse, especially in places with heavy flow.

2.Groynes or Spurs: Usually constructed of concrete or rocks, these structures stretch from the riverbank into the river. The goal is to change the river's flow, lessen bank erosion, and divert water away from locations that are susceptible.

3. Hard Points: Rigid, localized constructions positioned at strategic locations along a riverbank to fend against erosion. The goal is to stabilize and protect the areas of a riverbank that are most severely eroded.

4. The Guide Bund: Long, embankment-like constructions used to direct a river's flow and safeguard nearby infrastructure, including communities or bridges. The goal is to prevent uncontrolled wandering by controlling the direction of river flow, especially close to hydraulic infrastructure.

Figure: Crest of Guide Bund

Figure: Top View of Guide Bund Proposed for Matlab Uttar Bridge

5. Dredging : The procedure of employing specialized machinery to remove silt and debris from the riverbed. The goal is to enhance water flow, increase channel capacity to reduce flooding, and deepen rivers for navigation.

6. Loop-Cuts :  Artificial channels or shortcuts traverse a river's meanders. The goal is to straighten the river in order to decrease meander loop sediment deposition, increase flow velocity, and shorten its length.

7. Crossbars : Structures that are partially or fully submerged and positioned across a river to regulate water flow and sediment transport are known as submerged structures. The goals are to regulate water flow in braided rivers, stabilize river channels, and reduce silt deposition.

8. Management of Sediment : Methods for managing the flow, accumulation, and withdrawal of sediments in a river system. Preventing excessive sedimentation, enhancing water quality, and guaranteeing ecosystem health and sustainable river navigation are the goals.

The term "coastal management" describes the methods, procedures, and laws used to manage coastal areas sustainably while striking a balance between social, economic, and environmental goals. In addition to encouraging sustainable development and protecting ecosystems, the main objective is to reduce hazards including erosion, floods, and habitat loss.

Figure: Regulator

measures, plans, or interventions aimed at improving the efficiency and state of waterways to

enable safer, more dependable, and more efficient vessel movement are referred to as measure

for navigation enhancement. These steps are intended to resolve operational, environmental,

and physical issues that have an impact on navigation.

Important Elements of Navigation Improvement Initiatives: 

Physical modifications: Dredging is done to make navigation channels wider and deeper. stabilization of riverbanks to preserve channel integrity and stop erosion. removal of impediments such silt deposits, rocks, and rubbish.

Hydraulic Constructions: Building or enhancing weirs, dams, and locks to regulate water levels.To control flow and sediment deposition, groynes, revetments, or breakwaters can be installed.

Aids for Navigation: installation of lights, markers, and buoys to improve navigation safety. GPS and AIS (Automatic Identification Systems) are examples of electronic navigation systems. Regulation of Flow: maximizing reservoir discharges to keep water depth adequate during arid seasons. changes to flow patterns to lessen eddies or turbulence in the channel.

Aspects of the Environment: using environmentally friendly dredging techniques to reduce disturbance to the environment. juggling the necessity for navigation with the preservation of biodiversity and ecosystem.

Operational Actions: putting in place measures for managing vessel traffic to ease congestion. enforcing safety rules regarding vessel sizes and speed limitations.
Upkeep and Observation: routine examinations of buildings and navigation routes. monitoring water levels and flow parameters in real time.

"Measures for Navigation Enhancement," the main idea, is linked to five distinct measures, each of which is shown in its own box. These actions are: The term "dredging and dredged material management" refers to the process of clearing sediments from streams in order to preserve or deepen them and efficiently handle the dredged materials. The second step, 

Riverbed Armouring & Sediment Management, is controlling sediment movement for easier navigation and strengthening the riverbed to stop erosion. The process of physically removing debris or obstacles to increase the waterway's depth and flow is known as "excavation." 

Locks and Canals - Structural interventions that control water levels in navigation routes or allow for passage across uneven terrain.

Waterway Mapping- Producing thorough surveys and maps of waterways to improve the effectiveness and safety of navigation.