Khosla's theory is fundamental in designing hydraulic structures like weirs and barrages on permeable foundations. The exit gradient, which determines the safety against piping or undermining, is calculated based on the ratio of the floor width to the depth of the cut-off wall. This relationship helps engineers ensure the stability of structures against seepage forces.

Freeboard is a critical safety margin in dam and canal design. It provides a buffer zone above the maximum expected water level to account for wave action, surges, or settlement, ensuring that water does not overtop the embankment and cause structural failure.

A.N. Khosla developed the 'Method of Independent Variables' to analyze the seepage flow beneath hydraulic structures. This method allows engineers to calculate the uplift pressure and exit gradient by breaking down complex structures into simpler, standard forms, providing a more accurate design approach than earlier creep theories.

Rainfall intensity is a measure of the rate at which rain falls, typically expressed in units of depth per unit time, such as millimeters per hour (mm/hr). It represents the concentration of precipitation over a specific duration, which is a fundamental parameter in hydrology for calculating runoff and designing drainage systems for agricultural fields.

Lining irrigation water courses with impervious materials like concrete or plastic is primarily done to prevent seepage losses. Seepage occurs when water percolates through the soil of unlined channels, leading to significant water waste. By reducing seepage, lining ensures that a higher percentage of water reaches the target crops, improving irrigation efficiency.

R.G. Kennedy developed an empirical relationship for the design of stable irrigation channels in alluvial soils. His theory states that the critical velocity (Vo), which prevents silting or scouring, is proportional to the depth of the flow (D) raised to the power of 0.64. This formula, Vo = 0.55 * D^0.64, is a foundational concept in irrigation channel design.

A stable river is one that has achieved a state of dynamic equilibrium where the sediment load transported by the river is balanced by the sediment supplied to it. Consequently, the river does not undergo significant changes in its bed slope, cross-sectional geometry, or overall alignment over a long period.

A capacity curve (or elevation-capacity curve) is a graphical representation used in reservoir management. It plots the water surface elevation on one axis and the corresponding volume of water stored in the reservoir on the other, allowing operators to determine storage based on current water levels.

River training works encompass a variety of engineering interventions designed to guide, confine, or regulate the flow of a river. These structures are essential for protecting hydraulic installations, preventing bank erosion, and ensuring that water is directed safely through bridges, barrages, or dams, thereby maintaining the stability of the river channel and surrounding infrastructure.

This scenario is referred to as the 'worst condition' in dam and weir design. When the reservoir is at its maximum flood level and the downstream canal is empty, the uplift pressure is at its peak, creating the most critical stability challenge for the structure against sliding or overturning.