IS 10398:1982 is the Indian Standard (BIS) for guidelines for determination of design waves in coastal waters. This standard provides guidelines for determining the characteristics of design waves, such as significant wave height and peak period, for the design of coastal and marine structures. It covers empirical wave forecasting methods based on wind data (like SMB) and the statistical analysis of measured wave records to establish design conditions.
Provides methods and guidelines for determining design wave parameters for coastal and marine engineering projects.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Primary Hindcasting Technique | Sverdrup-Munk-Bretschneider (SMB) method, using wind speed, duration, and fetch length. | Calibrated numerical spectral wave models (e.g., SWAN, STWAVE). | USACE CEM |
| Representation of Sea State | Significant wave height (Hs) and significant period (Ts) or zero-crossing period (Tz). | Full wave energy density spectrum (e.g., JONSWAP) defined by Hs, peak period (Tp), and other spectral parameters. | ISO 19901-1:2015 |
| Short-Term Wave Height Distribution | Assumes Rayleigh distribution. | Rayleigh distribution is standard, but recommends alternatives like Forristall distribution in shallow water or for steep waves. | CIRIA C683 |
| Wave Breaking Criteria | Provides a simple depth-limited breaking criterion (e.g., Hb = 0.78d). | Uses more complex formulations that account for wave period and beach slope (e.g., Miche-Rundgren, Goda). | USACE CEM |
| Data for Long-Term Statistics | Wind records from meteorological stations and visual ship observations. | Long-term (30+ years) buoy data, satellite altimetry, and numerical hindcast databases. | USACE CEM |
| Directional Spreading | Generally treats waves as long-crested and unidirectional. | Requires consideration of directional spreading of wave energy, typically using a cosine-power function. | ISO 19901-1:2015 |