Water Resource Management

Introduction

• Water is the most important natural resource.
• A reliable water supply is crucial for farms.
• Water supply needs to be sufficient and clean for intended use.

Sources of Water

• Surface water includes rivers, lakes, farm ponds, and reservoirs.
• Underground water sources include wells and springs.

Classifications of Wells

• Depth: Shallow wells lift water 22 feet or less; deep wells lift water 22 feet or more.
• Construction: Dug wells are shallow and susceptible to pollution, driven wells are shallow, safe, and economical, bored wells are shallow and susceptible to pollution, tubular wells are deep and safe, and drilled wells are deep and safe.

Daily Water Requirements

• This table lists the daily water requirements for various uses.
• Each family member: 50-250 gallons minimum/household
• Horse: 40 gallons
• Milk-producing cow: 12 gallons
• Dry cow/steer: 12 gallons
• Hog: 4 gallons
• Sheep: 2 gallons
• 100 chickens: 6 gallons
• 100 turkeys: 18 gallons
• Garden hose (3/4 inch nozzle): 300 gallons
• Garden hose (1/2 inch nozzle): 200 gallons

General Pump Classifications

• Rotary: Uses gears, vanes, lobes, or screws to capture and move fluid from inlet to outlet.
• Reciprocating: Employs back-and-forth motion (like pistons or diaphragms) to pressurize fluids.
• Centrifugal: Leverages centrifugal force from rotating impellers to increase fluid kinetic and pressure energy.

Types of Pump Commonly Used for Pumping Water

• Centrifugal Pump: Impellers inside a casing draw water in and force it out through a discharge outlet, utilizing centrifugal force.

Axial Flow Pump

• A type of pump that develops most suction and discharge head by the propelling or lifting action of the impeller vanes on water.

Mixed Flow Pump

• A type of pump that combines features of both centrifugal and axial flow pumps. The head is developed partly by centrifugal force and partly by the lift of the vanes on the water.

Applications of Electric Pump System

• Domestic water supply
• Agro-industrial water supply
• Irrigation water supply

Pumps Terms

• Capacity: Amount of discharge at maximum efficiency.
• Discharge: Volume of water pumped per unit time.

Head

• Head: Amount of energy needed to lift and move water from a reference point.
• Friction Head: Equivalent head to overcome friction due to pipe flow and fittings.
• Static Suction Head: Vertical distance from suction water level to pump centerline.
• Static Discharge Head: Vertical distance from pump centerline to discharge water level.
• The formula is total head (Ht) = suction head (Hs) + discharge head (Hd) + friction head (Hf)

Water Horsepower (WHP)

• Theoretical power needed to pump water.
• WHP = Q × H / 273
• Q = discharge (m³/hr)
• H = vertical lift (m)

Brake Horsepower (BHP)

• Power needed to drive the pump shaft.
• BHP = WHP / pump efficiency (%)

Pump Efficiency

• Ratio of power output to power input.
• Efficiency (ξρ) = (WHP × 100) / BHP

Overall System Efficiency of Water Pump

• Efficiency of new and reconditioned electric water pump systems.
• New systems average 95% efficiency
• Reconditioned units average 60% efficiency

Cavitation and Priming

• Cavitation: Formation of vapor cavities due to pressure drops, often resulting in damage.
• Priming: Filling the pump with water to expel entrapped air, creating a seal in the casing.

Factors to Consider in Selection of Pump

• Well's head and capacity.
• Initial cost.
• Space required.
• Type of power unit and pump characteristics.
• Storage capacity, replenishment rate, and well diameter.
• Other potential pump uses.

Pump Laws

• Q1/Q2 = N1/N2
• H1/H2 = (N1^2) / (N2^2)
• BHP1/BHP2 = (N1^3) / (N2^3)
• Q = discharge
• N = rpm
• H = head
• BHP = brake horsepower

Geometrically Similar Pumps

• Q2/Q1 = (D2/D1)^3, H2/H1 = (D2/D1)^2, BHP2/BHP1 = (D2/D1)^5
• Q = discharge
• D = impeller diameter
• H = head
• BHP = brake horsepower

Pump Components and Controller

• The diagrams show submersible pump systems, pressure switches, float switches, pressure tanks, heaters, and various other components, along with diagrams of the controls like push button and magnetic switches.

References

• A list of references for the sources (included in full in user's document but omitted here per instructions).

Explore the essential aspects of water resource management, including sourcing, classifications of wells, and calculating daily water requirements for various needs. Understand the importance of clean and reliable water supply for agriculture and households.