Module 3&4 (IRRIGATION)

Open Channel Discharge Measurement

Open channel

  • natural/manmade conveyance structure which has a free surface at atmospheric pressure

  • a waterway, canal or conduit which a liquid flow with a free surface

Types of open channel

a. Natural channels

naturally exist on earth, irregular in shape

b. Artificial channels

made by human, regular geometric shape

Discharge

  • volume of water that is transported each second by a canal

Float Method

  • measures the surface velocity of the water with floating object, multiplying it by the width and ave. depth of channel

Irrigation and Drainage Structures

Irrigation - artificial application of water to the soil through various systems of tubes, pumps, and sprays. It is an essential requirement when rainfall is not secured or insufficient

  • Magat Dam - Municipality of Ramon Isabela

  • Pampanga River Irrigation System

    1. The Limbatangan Canal Irrigation System (CIS) Project was one of the priority projects by the province of Agusan del Sur funded through DA Philippine Rural Development Project (PRDP).

    2. The San Agustin CIS is tapped to irrigate farms in lowlands as well as rain-fed areas which is beneficial to farmers who depends on farming

    3. Communal Irrigation System (CIS) for agrarian reform beneficiaries in the Brgy. Calitlitan, Aritao, Nueva Vizcaya

    4. Macupa village in Leyte, Leyte / San Miguel, Leyte (Solar-powered irrigation system)

Common Methods of Irrigation

  1. Surface Irrigation - application of water by gravity flow over and across surface of the field

Entire field is either:

  • flooded (basin irrigation)

  • water is directed into small channels (furrow irrigation)

  • water is directed intro strips of land (border irrigation)

  1. Sprinkler Irrigation - rainfall like irrigation to crops

  2. Drip Irrigation - also called “trickle irrigation”, has drip pipe s with emitters at different spacing.

Common Types of Drainage System

  1. Municipal Drainage - primarily used in rural areas to discharge excess water.

  2. Highway Drainage- interception and removal of water from over, under, and vicinity of the road surface

  3. Agricultural Drainage - removal of surplus gravitational water from the surface and subsurface of farmlands.

Irrigation System

  1. Pumping station - directs water from the source of supply

  2. Conveyance system - transport water from the main pumping station up to the field ditches

  3. Distributing system - transport water through field ditches to the irrigated fields

  4. Field application system - transport of water within the fields

  5. Drainage system - removes the excess water that is caused by rainfall or drainage from fields