Forestry Interventions and Groundwater Recharge, Sediment Control and Carbon Sequestration in the Krishna River Basin

It is a known fact that human activities have a significant impact on global rivers, making the task of rehabilitating them to their former natural state or a more semi-natural state quite challenging. The ongoing initiative called “Rejuvenation of Krishna River through Forestry Interventions” aims to contribute to the overall river rejuvenation program in the country. In this context, the effects of forestry interventions on the Krishna River will be evaluated based on water quantity, water quality, and the potential for carbon sequestration through plantation efforts. To assess the outcomes of this study, various methodologies such as Soil Conservation Service Curve Number (SCS-CN), Central Ground Water Board (CGWB) and Intergovernmental Panel on Climate Change (IPCC) have been utilized to estimate water savings, reduction in sedimentation, and carbon sequestration potential within the Krishna basin. The projected results indicate that the implementation of forestry plantations and soil and moisture conservation measures in the Krishna River rejuvenation program could lead to significant improvements. Specifically, the interventions are expected to enhance water recharge by 400.49 million cubic meters per year, reduce sedimentation load by 869.22 cubic meters per year, and increase carbon sequestration by 3.91 lakh metric tonnes per year or 14.34 lakh metric tonnes of CO2 equivalent. By incorporating forestry interventions into the Krishna riverscape, it is anticipated that the quality and quantity of water flowing through the river will be positively impacted. These interventions will enhance water infiltration, mitigate soil erosion, and contribute to an improved vegetation cover, thereby conserving biodiversity. Moreover, they offer additional intangible benefits such as addressing climate change concerns through enhanced carbon sequestration potential along the entire stretch of riverine areas.

Change of lake area in the southeastern part of China's Badain Jaran Sand Sea and its implications for recharge sources

Understanding the relationship between the changes in lake water volume and climate change can provide valuable information to the recharge sources of lake water. This is particularly true in arid areas such as the Badain Jaran Sand Sea, an ecologically sensitive area, where the recharge sources of lakes are heatedly debated. In this study, we determined the areas of 50 lakes （representing 70% of the total permanent lakes in this sand sea） in 1967, 1975, 1990, 2000 and 2010 by analyzing remote-sensing images using image processing and ArGIS software. In general, the total lake area decreased from 1967 to 1990, remained almost unchanged from 1990 to 2000, and increased from 2000 to 2010. Analysis of the relationship between these changes and the contemporaneous changes in annual mean temperature and annual precipitation in the surrounding areas suggests that temperature has significantly affected the lake area, but that the influence of precipitation was minor. These results tend to su- pport the palaeo-water recharge hypothesis for lakes of the Badain Jaran Sand Sea, considering the fact that the distribution and area of lakes are closely related to precipitation and the size of mega-dunes, but the contemporaneous precipitation can hardly balance the lake water.

Nighttime sap flow of Acacia mangium and its implications for nighttime transpiration and stem water storage

Aims Nighttime sap flow of trees may indicate transpiration and/or recharge of stem water storage at night.This paper deals with the water use of Acacia mangium at night in the hilly lands of subtropical South China.Our primary goal was to reveal and understand the nature of nighttime sap flow and its functional significance.Methods Granier’s thermal dissipation method was used to determine the nighttime sap flux of A.mangium.Gas exchange system was used to estimate nighttime leaf transpiration and stomatal conductance of studied trees.Important Findings Nighttimesap flowwas substantial and showed seasonal variation similar to the patterns of daytime sap flowin A.mangium.Mean nighttime sap flow was higher in the less precipitation year of 2004(1122.4 mm)than in the more precipitation year of 2005(1342.5 mm)since more daytime transpiration and low soil water availability in the relatively dry 2004 can be the cause of more nighttime sap flow.Although vapor pressure deficit and air temperature were significantly correlated with nighttime sap flow,they could only explain a small fraction of the variance in nighttime sap flow.The total accumulated water loss(E_(L))by transpiration of canopy leaves was only;2.6–8.5%of the total nighttime sap flow(E_(t))during the nights of July 17–18 and 18–19,2006.Therefore,it is likely that the nighttime sap flow was mainly used for refillingwater in the trunk.The stem diameter at breast height,basal area and sapwood area explained much more variance of nighttime water recharge than environmental factors and other tree form features,such as tree height,stem length below the branch,and canopy size.The contribution of nighttime water recharge to the total transpiration ranged from 14.7 to 30.3%depending on different DBH class and was considerably higher in the dry season compared to the wet season.

Groundwater uptake of different surface cover and its consequences in great Hungarian plain

Introduction:Forest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century.The EU(European Union)promotes further afforestation;thus,15,000–18,000 ha are being forested each year,mainly in the Hungarian Great Plain.In terms of species used for afforestation,poplar plantations are preferred over native oak woodlands.The groundwater uptake of trees can be a significant water balance element of forested areas in shallow groundwater environments within the Hungarian Great Plain.Forests can cause water table depressions and subsurface salt accumulation in areas with negative water balance.This study examined the hydrological impact of forest cover in the Hungarian Great Plain.Within the framework of this research,climatic water balance,water table depth and salinity,subsoil layering,tree species and stand age were analysed as influencing factors.This paper compares the effect which an oak forest,a poplar plantation and a pasture have on groundwater uptake and salt accumulation.Results:The water table level was roughly 0.4–0.5 m lower beneath the oak forest and the poplar plantation than it was beneath the pasture.Forest groundwater use was 1.5–2 times higher than that of grassland.Groundwater uptake of oak forest was greater than that of poplar plantation during the monitoring period.Salt accumulation,which shows water use in the longer run,was slightly higher for poplar in deeper layers.Conclusions:The greater amount of groundwater used by trees does not lead to a higher salt uptake as only a slight accumulation of salt was measured beneath the forests.Overall,hybrid poplar was slightly less favourable than native oak when considering salinization effects.However,even greater groundwater uptake by trees over longer timescales could cause more significant salt accumulation under pronounced drought conditions due to climate change.

Role of forests in headwater control with changing environment and society

Forest practices in headwater catchments are related to environmental and social contexts.The aim of this study is to analyse the changing protective functions of forests in the upper plain of the Jizera Mts.(North Bohemia,Czech Republic)since the second half of the 19th century.With time,forests have gradually changed from native stands to spruce plantations(Picea abies),introducing exotic conifers(more resistant to air pollution),and,recently,back to more diverse mixed stands.The priority in pro-tective forest functions there shifted from flood protection to integrated control of water resources(quantity and quality).In the 1980s,forest-water interactions were degraded by consequences of extreme acid atmospheric deposition,forest die-back,and extensive clear-cut.In the Jizerka catchment,first signs of recovery were observed in the early 1990s.but.stream waters there are still affected by prolonged acidification.While reconstruction of stream water chemistry at Jizerka follows the drop of the acid deposition in some 5 years,the revival of stream biota takes 10-15 years.In 2071-2100,the pro-jected climate change shows rising annual air temperatures by 3.0-4.6℃,decreasing water yield by 65-123 mm,60%drop in'minimum residual discharge',and 20-30%rise in peak-flows.However,these projected environmental changes cannot substantially decline the high potential in water resource recharge,or,start reverse processes in recent recovery from acidification and radically affect the exis-tence of planned mixed forests in the upper plain of the Jizera Mts.

Fifty Years of Water Sensitive Urban Design, Salisbury, South Australia

Australia has developed extensive policies and guidelines for the management of its water. The City of Salisbury, located within metropolitan Adelaide, South Australia, developed rapidly through urbanisation from the 1970s. Water sensitive urban design principles were adopted to maximise the use of the increased rim-off generated by urbanisation and ameliorate flood risk. Managed aquifer recharge was introduced for storing remediated low-salinity stormwater by aquifer storage and recovery （ASR） in a brackish aquiter for subsequent lrngatlon. Ibis paper outlines now a municipal government has progressively adopted principles of Water Sensitive Urban Design during its development within a framework of evolving national water policies. Salisbury＇s success with stormwater harvesting led to the formation of a pioneering w aterbusiness that includes linking projects from nine sites to provide a non-potable supply of 5 ×10^6 m^3 year. These installations hosted a number of applied research projects addressing well configuration, water quality, reliability and economics and facilitated the evaluation of its system as a potential potable water source. The evaluation showed that while untreated stonnwater contained contaminants, subsurface storage and end-use controls were sufficient to make recovered water sale for public open space irrigation, and with chlorination acceptable lbr third pipe supplies. Drinking water quality could be achieved by adding microfiltration, disinfection with UV and chlorination. The costs that would need to be expended to achieve drinking water safety standards were found to be considerably less than the cost of establishing dual pipe distribution systems. The full cost of supply was determined to be AUD$1.57 m ＂ for non-potable water for pubhc open space lrngatlon much cheaper than mares water, AUD $3.45 m at that time. Producing and storing potable water was found to cost AUDS1.96 to $2.24 m .