Infiltration and Runoff The Water Cycle Infiltration and Runoff

Parts of the water Cycle • Atmosphere • Condensation • Evaporation • Evapotranspiration • Freshwater storage • Groundwater flow • Groundwater storage • Ice and snow • Infiltration • Oceans • Precipitation • Snowmelt runoff • Springs • Streamflow • Sublimation • Surface runoff

Ground water begins as precipitation

Infiltra tion permeation of a liquid into something by filtration. Water Cycle Infiltra tion permeation of a liquid into something by filtration.

Factors Affecting Infiltration Water Cycle Factors Affecting Infiltration Precipitation Amount and characteristics (intensity, duration, etc) Seeps into stream beds over a period of time stream will often continue to flow when it hasn't rained for a long time and where there is no direct runoff from recent precipitation. Base Flow Water in streams have a sustained flow even in periods of no rain This comes from groundwater seeping into the stream and bank

Factors Affecting Infiltration Water Cycle Factors Affecting Infiltration Soil Characteristics Clays absorb less water at a slower rate than sandy soils Results in more runoff overland and into the streams Soil Saturation Soil that has maxed out on amount of water that can be absorbed Causes excess water to become runoff

Factors Affecting Infiltration Water Cycle Factors Affecting Infiltration Land Covers Vegetation slows movement of runoff Gives more time for water to seep into groundwater Impervious Surfaces “fast lane” for rainfall water goes directly into storm drains which drain directly into streams Agriculture and Tillage of land Where water would normally infiltrate becomes stagnate and ends up in the streams

Factors Affecting Infiltration Water Cycle Factors Affecting Infiltration Slope of the land More of a slope = faster runoff and less infiltration Transpiration (evapotransipration) Some infiltrated water only makes it past the initial ground layer Plants use this water and it gets evaporated back into the atmosphere

Subsurface Water Water Cycle As precipitation infiltrates into subsurface soil, it creates a saturated zone and an unsaturated zone Unsaturated Zone voids—that is, the spaces between grains of gravel, sand, silt, clay, and cracks within rocks—contain both air and water Although a lot of water present. cannot be pumped by wells because it is held too tightly by capillary forces Soil-water zone upper part of the unsaturated zone crisscrossed by roots, openings left by decayed roots, and animal and worm burrows, which allow the precipitation to infiltrate into the soil zone Water is used by plants but can evaporate directly to the atmosphere.

Infiltration Replenishes Aquifers Water cycle Infiltration Replenishes Aquifers A very slow, naturally occurring process groundwater moves slowly through the unsaturated zone and the aquifer The rate of recharge is important If the aquifer that underlies the plains of Texas and New Mexico were to be emptied…it would take centuries to refill it due to the small amount of rain this area gets If the shallow aquifer in the coast of Georgia and Florida were to be emptied, the replenishment would be almost immediate due to the high amounts of rain the area receives.

How do Humans help? Artificial Recharge Water Cycle How do Humans help? Artificial Recharge gives infiltration a natural push in some places, they pump water out of the aquifer faster than nature replenishes it can be lowered by the excessive pumping. Wells can "go dry" and become useless. In places where the water table is close to the land surface and where water can move through the aquifer at a high rate, aquifers can be replenished artificially

Artificial Recharge Rapid Infiltration Pits water cycle Artificial Recharge Rapid Infiltration Pits spread water over the land in pits, furrows, or ditches, or to erect small dams in stream channels to detain and deflect surface runoff, thereby allowing it to infiltrate to the aquifer Groundwater injection construct recharge wells and inject water directly into an aquifer

How are permeability and porosity different? When does runoff occur? Water Cycle Video https://study.com/academy/lesson/runoff-infiltration- definition-process.html#lesson How are permeability and porosity different? When does runoff occur? What is the term for the speed at which water can infiltrate soil? What is the term for how much water soil can hold? What are some facts about evaporation?