Water and Carbon case studies

Human impacts on the river Itchen - Urbanisation

250 acre Barton Farm development - tarmacing of roads/development projects reduce infiltration - Hampshire’s groundwater management plan provides specific action plans for 10 Hampshire settlements at risk of groundwater flooding

Human impacts on the river Itchen - Population Gowth

Growing population provides extra pressure on water supply - expected to grow 4.8% over the next decade

Human impacts on the river Itchen - Climate change

This would increase the risk risks associated with obstruction and low flow leading to a 20% reduction of summer flows at 20% increase in winter flow

Human impacts on the river Itchen - Agricultural practices

Compacted soils and water courses which have been physically modified in order to get rainfall out of the sea as fast as possible and reduce the amount of water is available to be stored in the catchment (62% is rural)

Human impacts on the river Itchen - Catchment management

Has been given a high level of environmental protection where more water is protected from ground water abstraction - CAMS - strategy provides licenses to abstract water and balances ecological domestic and business needs

Human impacts on the river Itchen - Water storage projects

Havant Thicket Winter Storage Reservoir - £103m project - collaboration between Portsmouth and Southern Water aimed at providing resilient water supply to region - reduces abstraction on chalk rivers, biodiversity net gain

Human impacts on the river Itchen - Abstraction

Itchen and tributaries are supplied by groundwater particularly during times of low rainfall - rover classified as seriously water stressed due to comparatively low rainfall combine with particularly high levels of water being abstracted

River Itchen nature

Elongated basin, subdued hydrograph to the rural north, gets flashier in the urban south, few tributaries, predominantly non urban catchment

Human practices along the Itchen

Watercress Growing, wastewater discharge, arable farmland - deforestation

Winchester Floods 2014 - Natural Factors

300% of average february rainfall, 75% of the months rainfall in 5 days, Itchen burst banks - lots of groundwater flooding

Winchester Floods 2014 - Human Induced Factors

Impermeable surfaces directly surrounding river, poor urban planning, ow lying houses built on flood plane

Winchester Floods 2014 - Impacts

River Park Leisure Centre Closed temporarily, £1.6 million on repairing defences, Homes flooded, possessions destroyed, residents evacuated, estimated cost at £68.5 million plus Insurance Costs, disruption to education, business and road and rail travel, road closures and rail cancellations, sewage contamination in homes and parks such as Water Lane, tree fall

Winchester Floods 2014 - Management

Sluice gate control flood levels at Durngate, Planning controls, environment agency and local councils erected permanent barriers on Water Lane and Park Avenue, Hampshire Fire Service brought 2 high volume pumps, Winchester City Council - Repair and Renew Grant Schemes, Business owners can claim for losses, Sandbagging on roads, £1.6 million spent on defence repairs, Road closures at Water Lane, Park Lane and Andover Road, Multi agency approach between the Firefighters, Navy, council workers, police officers and environment agency workers joining forces to build a 70 foot flood barrier and creating artificial lakes to ease the strain on Winchester

Amazon rainforest location

Majority of northern Brazil and South America are in the drainage basin of either side of the equator in the Western hemisphere spinning 670 hectares in nine countries

Importance of the Amazon

The worlds largest rainforest and one of the most bio diverse with 300 billion trees and 15,000 species. It's a fifth of earth’s biomass carbon, home to 34m people

Scale of the Amazon carbon store

76B tonnes of C in 2019, forming part of the 1-3GtC rainforest sink, above ground biomass increases by 0.3-5% per year, rising productivity due to higher atmospheric CO2 - negative feedback - Trees grow faster ut die younger, surge in death of trees

Scale of the Amazon water store

Rio Negro - a tributary - is the 2nd largest river globally in terms of water carried, 900m deep, 14km wide mouth, average rainfall of 2300mm annually - can exceed 6000mm - up to half rainfall may never reach the ground due to interception and evapotranspiration, where 48% falls again as rain forming a parially closed system, 15% of freshwater running into oceans is from the Amazon

Human changes to the Amazon water cycle

Slash and burn facilitates southern evaporation of water previously retained in the forest canopies, any moisture evapourates from deforested areas to form columbus clouds with no rain, deeper roots pump more moisture to the surface producing 20-30% more air humidity and 5-20% more soil moisture than pastures

Human changes to the Amazon carbon cycle

19368km² per yer in deforestation from 2000-2007, area larger than Greece destroyed, Brazil is 4th largest polluter, 75% of emissions coming from deforestation and land use change - 59% of this from burning/deforestation in the Amazon using slash and burn, if destroyed the forest carbon store will be released to the atmosphere, forests absorb 11% more solar radiation than pastures

Impacts on changes in the Amazon on vegetation

Net loss of forests in the Amazon basin, WWF estimates 20% already lost, and will be 27% by 2030 if the current rate continues, climate change changes the environment which some species require, leading to affected survival chances

Impacts on changes in the Amazon on soils

Soils contain 4-9kg in upper 50cm, while pasturs only contain 1kg/m², when forrests are cleared and burned 30-60% of CO2 is lost to the atmosphere, unburned vegetation decays and is lost within 10 years, soil fungi and bacteria die, soils get exposed to heavy rainfall following forrest clearance which washes away the topsoil, and washing the remainder into rivers decreasing soil structure

Impacts on changes in the Amazon on rivers

changes in precipitation, extreme rainfall and seasonality have lead to overall reduction in discharge, silt increase causing disruptions to river transport routes, flash flooding, destroying freshwater ecosystems, affect locals water supply

Mitigation of environmental change in the Amazon

National and international agreements - The Latin America Technical Cooperation Network n Watershed Management (REDLACH), Amazon Cooperation Treaty Organisation (ACTO) promotes enrichment of degraded forests only using native species, biofuel production aim to compete with ethanol from sugar cane by 2030, reforestation - 2% of Brazil’s industrial timber is from replanted trees, creation of national parks and forest reserves such as Rara Rainforest reserve