According to the US Geological Survey, furrow irrigation is a form of surface irrigation where trenches are used to deliver water to rows of crops. Most modern farming operations replaced this method with mechanized spray irrigation systems.
Other forms of surface irrigation are still in use throughout the world today. These include leveling fields to allow gravity to spread water evenly across the land, controlled flooding of fields at regular intervals and the capture and reuse of runoff from flooding in order to avoid waste. Surface irrigation methods are inexpensive compared to spray methods. They also lose less water due to evaporation.