To conduct underwater observations for identify the leakage path within the foundation gallery of Dhamni Dam under Surya Major Project Taluka Vikramgad, District Palghar.

सुर्या मोठा प्रकल्प ता. विक्रमगड जि. पालघर प्रकल्पांतर्गत धामणी धरणाच्या तळपायातील सज्जा (Foundation Gallary) मधुन पाण्याच्या होणा-या गळतीचा मार्ग शोधण्यासाठी Under Water Observation करणे.

Underwater Videography High-definition underwater videography will be conducted along the dam structure, covering the upstream face, downstream regions (if accessible), intake areas, and adjacent reservoir bed. The survey will document the condition of submerged concrete surfaces, joints, gates, and structural interfaces. It will capture visual evidence of cracks, spalling, erosion, biofouling, debris accumulation, and any unidentified underwater anomalies around the dam. The inspection shall utilize an OIS-enabled atleast 12 MP HD camera along with a 4K camera featuring enhanced low-light visibility, ensuring stable, clear, and detailed imaging even in turbid and low-illumination conditions. The inspection activities shall account for submerged structural conditions up to a maximum depth of 58.08 m across the entire dam length of 623 m, ensuring complete coverage of all critical underwater components.

Underwater Sonar Scanning Sonar scanning will be carried out within the frequency range of 750 kHz to 1.2 MHz along the dam's upstream face and adjoining reservoir area to map low-visibility zones and detect submerged features. The survey will generate acoustic imagery to identify anomalies, scour pockets, debris, and any objects near the dam wall, intake points, and reservoir bed. This ensures reliable detection even in turbid conditions. Quantification of the identified defects shall be included in the final 3D output.

Data Analysis & Reporting All collected sonar, video, and bathymetry data will be processed using geo-referencing, interpolation, noise reduction, mathematical modelling, and digital reconstruction techniques. This will generate refined depth profiles, enhanced underwater visuals, anomaly/object mapping layers, and a 3D model of the reservoir near the dam. With all these a comprehensive inspection report, detailing all findings, will be prepared and delivered. The 3D model of each required defect shall be provided to enable a comprehensive understanding of the structural condition.

Mobilization and demobilization Mobilization and demobilization of equipment, UV systems, and technical crew to and from inspection site.