It depends which NCIS you are referring to. CBS broadcasts NCIS, NCIS: Los Angeles, and NCIS: New Orleans. NCIS is aired on Tuesdays 8/7c. NCIS: Los Angeles is aired on Mondays 10/9 c. NCIS: New Orleans is aired on Tuesdays 9/8c.
Whereas groins are built to change the effects of beach erosion, jetties are built so that a channel to the ocean will stay open for navigation purposes. They are also built to prevent rivermouths and streams from meandering naturally.
A sandbag is a sack made of burlap or woven polypropylene that is filled with sand or soil and used for such purposes as flood control and military fortification. Sand bags are an excellent choice for the construction of levees, berms, dikes and barricades for erosion control, flood walls, and traffic control. Sandbags may be used during emergencies when rivers threaten to over-flood, or a levee or dike is damaged.