Sub-humid to Arid Zones of the World Experiencing increasing Groundwater Depletion and Withdrawals

From 1960 until 2000, the amount of groundwater withdrawn and depleted from climate changes has increased in sub-humid to arid areas of the world. Measures of groundwater depletion and withdrawal were found with data of decreasing volumes of water percolating back underground, and the amount of groundwater withdrawals, to calculate groundwater lost per year that is not recharged. Water volumes in two soil layers and the groundwater layer were all measured in these regions of the globe, separated into multiple cells. The results showed an increase of around 57 km3 per year in groundwater depletion. This consists of 36 (±10)% of the global groundwater withdrawn annually, 2(±0.6)% of the annual recharge, 0.8(±0.1)% annual global runoff, and 0.4(0.06)% of global evaporation. Though uncertain, this decrease in groundwater supplies is likely to present an added sea-level rise of 0.8(±0.1) mm per year.  This study compiled by Wada et al. concerns only regions of sub-humid to arid climates. –Darien Martin

Wada, Y. Van Beek, L., Van Kempen, C., Reckman, J., Vasak, Slavek., Bierkens, M., 2010. Global depletion of groundwater resources. Geophysical Research Letters 37, 1–5.

          When performing this study, uncertainties in the data set results were caused by a number of variables. Wada et al. did not know the specific location of wells or irrigation systems, and it was assumed that they were nearby where the water was used. It was also assumed that demand for water correlated with water use. Demand was used to calculate estimated groundwater use.
          First, the volume of groundwater was measured using a model that determined the volume of groundwater recharge. Volumes of water were tracked among two soil layers, the groundwater layer below, evaporation, precipitation, and  snowmelt. two soil levels above the groundwater layer, evaporation, precipitation and snowmelt. Regions were organized into grids of  0.5°latitude by 0.5°longitude when measured. In each grid, soil types, vegetation, surface water body shapes, and groundwater area depth when measuring the cycling water volumes. Groundwater recharge was determined by the amount of water moving from the lower soil layer to groundwater storage.
          Next, the volume of water withdrawn in each grid was determined.  The international Groundwater Resources Assessment Centre’s online database was used which gathered the rate at which of groundwater was extracted in many countries.  Water was extracted at higher rates in Northeast China, much of Europe, the US, Iran, India and Pakistan. The rate of extracted groundwater in 2000, in all semi-humid to arid climates, is 734 (±82) km3 per year.
          Lastly, annual groundwater depletion from 1960 until 2000 was calculated by subtracting groundwater recharge from groundwater extraction.  A significant global trend in increasing groundwater depletion was found.  Most severely effected areas are in Iran, Yemen, Southeast Spain, the Central Valley of California, and Northeast China. 
Although uncertain due to offsets of reservoir storage, this increase in groundwater depletion is estimated to have caused 25(±3) % of the sea level rise per year. This was estimated using the volume of groundwater released from storage data and the amount of that will end up in the ocean through runoff and evaporation followed by precipitation; assuming that all other variables of climate stayed constant. Groundwater depletion trends will likely continue to increase in rates, and to cause sea levels to rise (Drouiche et al.).

Compiling Data To Predict Future Water Supply and Demand- Russia

Russia’s Shiklomanov et al. (2011) compiled data at the State Hydrological Institute from various sources on the past and future characteristics of renewable water supply. All federal districts were evaluated for existing data from 1930 to 2005, and then predictions were made into the year 2020. The distribution of resources is extremely uneven with around 30 times more water volume available in Eastern and Siberia federal districts, than in Nothwestern and Ural federal districts. Water use in Russia breaks down to 63% for industry, 22% municipal, and 15% for agriculture. The areas with the densest populations have a limited supply. In general, however, Russian water resources will increase, and efficiency in usage is predicted to continue to improve. An increase in water supply per capita is predicted for many regions, but due to increasing population and activity, and larger amounts of agricultural irrigation in southern regions, along with decrease in supply may decrease water availability. –Darien Martin
Shiklomanov, I., Babkin, V., Balonishnikov, Zh., 2011. Water resources, their use, and
water availability in Russia: current estimates and forecasts. State Hydrological Institute. 38, 139–148.

          Water resources in Russia have been increasing overall from 1936–2006; however, demand has as well. For past supply trends, data were collected from watersheds with limited human use. From 1983 to 2006, the groundwater supply increased from 17.9 km3/yr to 400km3/year while the safe amount needed changed from 17.5 to 33.5km3/year. Runoff has increased from 20–40% in the most regions. More of this runoff increase occurs during winter and fall. Runoff of freshwater into the Arctic Ocean has increased by 210km3/year in the last 12 years.  A direct correlation with this increase and the increase of air temperature has been observed.
          Future water resources are expected to continue to increase (except in the South, Southwestern Siberia, and Chernozem Center federal districts.) To predict future changes in river discharge, data from the past 25 years were extrapolated with general circulation climate models, and climate change measured from already existing data. Overall, river runoff throughout the country is projected to increase 8–10%, however southern regions mentioned above will lose 5–15% of their runoff. In regions with increasing runoff, there will likely be more discharge especially during winter and summer, and to a lesser extent, during spring floods.
          Overall use is likely to remain the same or decrease in northern regions and to remain the same or increase in southern regions. Municipal water consumption is projected to decrease from improved water use practices; 20% less will be used by 2020. Agricultural use will likely increase from 2005 to 2020, as more irrigation is added; however, irrigation expansion will not exceed levels from the 70’s and 80’s. Industrial water use, will likely decrease or remain the same due to increases in use of recycled water.
          Supply is predicted to increase in regions with more than 95% of the water. The remaining 5% of regions are predicted to decrease have some of the densest populations. Improving water use practices will also help to create more water availability and help to minimize increases in industrial and domestic uses, however growing agriculture will still likely increase water shortages in agricultural regions.

Predictions, in China, on Changes in Water Resources and its effect on Agriculture Production from Climate Change

Piao et al. examined various climate change models extending to future projections of change, predicted future changes in water supply available, and how these components will effect agricultural production. China produces agriculture for 22% of the world population on only 11% of its arable land. Their main crops are rice, wheat and maize. Northern and Northeast China is dryer, while Southern China is wetter. Trends will vary from region to region. Precipitation trend will experience opposite trends from Northeast to South. Glaciers melting and changes in precipitation will each affect available runoff differently. These changes will be paired with projected increasing demand for water with industrial and agricultural growth. Without taking into account CO2 emmisions, overall crop production is projected to decrease. This decrease, however, will be countered with new agricultural practices and technologies. –Sky Martin
Piao, Shilong et al. 2010. The impacts of climate change on water resources
and agriculture in China. Nature 467, 43–51.

          Since 1960, the climate of China has been increasing in temperature by about 0.04°C each winter and 0.01°C each summer. It is certain from models that a warming trend will occur, but uncertain whether it will increase in rate. Two models demonstrate an increase in summer warming which would increase evapo-transpiration and decrease water supplies.
          Water supply is affected by both precipitation and glacier-melt. There is no general precipitation change for the country, but regional trends were found. The north and northeast have been declining in precipitation in summer and autumn with 12% lost from 1960. The South has had increasing precipitation in summer and winter. Predictions for future precipitation trends are highly uncertain.  More drought and flood are predicted for Northwest China and the Lower Yangtze River and less for the northeast and the northwest of the Yangtze. One scenario predicts longer drought periods in the Northeast and less in the Northwest, while another predicts a decrease of drought in the northeast. Piao et al. suggest that more thorough studies on soil moisture and droughts in the twentieth century would help to formulate a more accurate prediction.
          A decrease in glacier recovery of ice ever year is more certainly predicted than precipitation trends. This will cause more runoff in the spring and early summer, and less water in late summer for the first few decades, and result in an overall water loss of 10-67% by 2100. Runoff may peak around 2030­–2050 from the reduction of ice, but will then decrease.
          There are conflicting models that predict how yields will change over the next 40 years, extrapolated from data from the 1970s to 2000. Increase in temperature itself will benefit irrigated crops and hinder rain-fed crops. Rice will benefit from an expanded territory to be grown in. Temperature will also cause an increase in disease and pests’ terrain as well. Overall climate change and water shortages alone are predicted to reduce crop production by 2050: 4–14% less rice, 2–20% less wheat, and 0–23% less maize. This may be countered by the fertilization of increased CO2concentrations, but CO2 increase could be eliminated by the harms of increased ozone exposure.
          Overall crop reduction due to climate change and water stress from diminished supplies and increased demand is projected for agriculture in China. It’s very uncertain how precipitation trends will affect future water supplies, but glaciers are more certainly predicted to shrink, eventually providing less water. Crop production overall will decrease, however, large technological advancements are being made and could continue to prevent or delay pressures of climate change and water shortage.

Asia’s Five Major Watersheds’ Resources Threatened by Climate Change

Asia’s has five major water basins all above 2,000m above sea level: the Indus, Brahmaputra, Ganges, Yangtze, and Yellow river basins. Together, these basins provide for rivers that provide water supply for more than 20% of the global population. Climate Change will bring changing trends in temperature and precipitation which will affect the amount of water available for people. The hydrolic affects leading to a change in water availability will vary greatly from watershed to watershed, but overall, there will be a decrease in water equivalent to a supply for 4.5% of the total population served. The Indus and Brahmaputra basins will have the highest water discharge decreases, and due to increased rainfall, the Yellow is projected to have a slight increase in discharge.–Darien Martin
Immerzeel, W., Beek, L., Bierkens, M., 2010. Climate change will affect the asian
water towers. Science AAAS 328, 1382–1385.

               
          To project water supplies for 2046-65), Immerzeel et al. measured the amounts of discharge, and water supply for each of these basins, and investigated the effects of melt water volume from ice and snow on discharge downstream. They then predicted future changes in ice coverage, and used this data to project the discharge and resulting water supply from each water basin. Other components affecting water discharge were factored in, such as amount of precipitation, before predicting water resource availability.
          In order to assess how ice and snow amounts effect discharge volumes, Immerzeel et al. used a Normalized Melt Index which is: snow and glacier discharge volume divided by downstream discharge. Upstream discharge was found using a snow melt runoff model, and downstream discharge was found using by subtracting the amount of upstream glacier discharge that had evaporated. It was found that the Indus and Brahmaputra received the largest percentages of their discharge from glacier melt; especially the Brahmaputra with glacier melt of 151% of downstream discharge. To determine ice storage, a gravity model combined with precipitation trends was used. Both ice storage, was tested to predict past discharge amounts, and predictions were accurate in comparison to past numbers.
Next, they predicted ice volumes and discharge for each basin in 2046 to 2065 using general circulation models, which include a number of climate change factors. These results were inconclusive, predicting a decrease in ice for the Ganges basin, and an increase for the Indus. Lastly, upstream water availability was assessed beside water demand in terms of crop yield and energy to project effects on future food supply.
          Results found that discharge from all rivers would increase for a short period when glaciers shrunk, but would then decrease in all basins except for the Yellow River, which had an overall increase of 9.5% water discharge upstream. Decrease in glacier area and water discharge was countered but not reversed (besides in the case of the Yellow River), by increases in annual precipitation predicted. The decrease in discharge may cause the Bramaputra and Indus, and Ganges rivers to become seasonal. The Indus and Brahmaputra will be most affected by climate change due to the high percentage of their water supply coming from glacial melt.

          This will create an overall stress on food supply. Population on the Yangtze is the largest, the Ganges is most densely populated, and the Indus, Ganges and Yangtze have the most agriculture to support. The Yellow River may provide for an increase in food availability from increased water supply, but the Indus and Brahmaputra are in danger due to their large irrigation networks fed largely by glacial melt. 

Algeria’s New Plan; Growing Capacities of Desalinization Plants

Algeria has experienced harsh droughts over the past twenty years. The driest regions of the west have suffered the most. Algeria has experienced increasing water stress due to growing populations, industry, and water demands of each individual in dry conditions. Drouiche et al. evaluates the future of desalinization of both brackish and seawater in Algeria until 2015. After plans to create more reservoirs were deemed inadequate, the Algerian Government supported plans for large desalination projects. There are also plans to ship water inland from existing coastal dams on the coast inland as water supply from desalinization plants becomes available by the sea. Technology is improving, and making it a more realistic option for supplying large amounts of water around the world. 11 large desalinating plants have been built in Algeria, and 5 more are underway.
Darien Martin 
Drouiche, N., Ghaffour, N., Naceur, M. Hacene, M., 2011. Reasons for the fast growing
seawater desalination capacity in Algeria. Water Resources Management 25, 2743–2754.

          A century ago, a long drought began and Algeria’s Minister of Water Resources planned for dams to pump water of the foothills up to the High Plains. This would aim to relieve the problem of denser populations collecting along the coasts. However, the reservoir levels were sinking. After evaluation it was decided that reservoirs wouldn’t supply an adequate increase in water due to negative predictions for little rainfall, actual building of the dams, physical losses from dams, overuse of groundwater, uneven distribution that would occur, and contaminated surface waters.
During the drought, 21 small desalinization sites were assembled which worked to help people through the drought. Future larger desalinization plans were then assessed and found to be cost effective, and provide more water, over the long run, than new dams would provide. Algeria has many coastal areas that would be able to utilize supplies from plants locally. Other benefits include a virtually endless supply, desalinization processes that don’t pollute waterways, and technology that has advanced and become affordable. The Ministry of Water Resources plans to move water supply from coastal dams inland to the High Plains, and then use the desalinated seawater for the coastal populations.
          Algeria started building desalinization plants in 2003. These were mostly built by oil companies, and used thermal techniques of Multi Stage Flash (MSF) and thermo-compression. The Algerian government planned a new desalinization program. All plants were planned under “Build, Own, Operate” contracts (except in Kahrama). This requires that the same people who design the plants build and manage them, so that plants built are less likely to experience operation glitches. The Algerian Water Authority and the Algerian Energy Company built 16 large plants, 11 of which are complete. Each produces 100,000 to 500,000m3/day.  The new plants use reverse osmosis; except for one in Arzew, and another being built in Hamma which both use Multi Stage Flash. The largest seawater reverse osmosis plant is planned to be built in Maqtaa. When all plants are complete, they will produce 1,461 m3/day of fresh water. 70% of the produced freshwater is used for cities and homes and 27% is used for industry. From 2011 to 2015, water supply coming from the sea is expected to increase 2,433,000 m3/day, and supply from brackish water by 248,000m3/day.
          Desalinization is a growing possibility throughout the world. The world’s desalination capacity is growing at a rate of 55% per year. It now has the capacity to produce 60 million m3/day of desalinated water, and in 2015 is projected to grow to 100 million m3/day. Now, 63.6% is made with a membrane process of reverse osmosis, and 34.8% using thermal processes. Algeria, Spain and Australia have the highest rate of desalination capacity growth in the world. Saudi Arabia, the US, and United Arab Emirates have built plants to make the highest capacities of desalinated water since 1945.
          Algeria now has a plan underway to become more resilient to its long droughts. Through an integrated plan of transporting water from the coastal dams to highlands, and implementing desalinization on the coasts, more water will be available to a growing population, industry and water demand. In addition to this plan of 16 mega-plants, The Algerian government has been supporting this plan to secure water availability to people by subsidizing higher desalinated water costs to fix water prices.

Possible Solution to Increasing Water Stress in the Middle East

Many parts of the world have started using treated sewage water for reuse such as irrigation or even drinking water. There is much potential to implement aquifer storage recovery (ASR) systems that reuse treated effluent sewage (TSE).  To recycle TSE in the Middle East, further knowledge and testing of system sites for water recycling, more secure safe, large storage places, site specific wells, and thorough monitoring of system sites is needed. The hydrogeologic data collected at this point is not extensive enough to determine how water will behave in many sites. Water can be used in the dry season from these storage sites, and many harmful compounds will start to break down over time. Maliva et al. shows in this paper that TSE can be broken down to pure potable water. –Darien Martin
Maliva, R., Missimer, T., Winslow, F., Herrmann, R., 2011. Aquifer storage and recovery
of treated sewage effluent in the Middle East. Arabian Journal of Science and Engineering 36, 63­ – 74.

 In order to be cost-effective and help the Middle East meet its supply and demand with water, storage areas should provide long term holding capacity. Above ground systems don’t meet this requirement. Storage tanks, which could hold enough water for long-term storage, would be too expensive, and surface reservoirs have large evaporative loss and demand lots of land. Underground storage in aquifers is best suited for the job. Managed aquifer recharge (MAR) is idealized; using wells or added surface water to fill aquifers keeps them at a high enough water pressure to prevent salt-water intrusion. In these systems, water can be is added and drawn from the same well, or added through infiltration basins.
Maliva et al. presents two approaches to storage and recharge of water in the Middle East.  Water can be either physically or chemically bounded.  Physically bound storage is enclosed by essentially impermeable concrete or rock on bottom and sides, and adding water and increasing pressure maintain MAR. Chemically bounded ASR systems include a freshwater body injected into brackish water. Brackish water is flushed away and then only freshwater surrounds the well. A zone of mixed water forms between the two water qualities, but separation can be kept with the right levels of pressure.
          Pathogenic microorganisms and chemical contaminants are found in TSE before treatment. Pathogenic microorganisms coming from animals’ intestines are a top concern and can infect a person who is exposed only once. The decay or removal of these microorganisms in Middle East groundwater may take several days to weeks in these warm waters.  Chemical contaminants are also found in aquifer water from industrial activity, wastewater, and treatment chemicals. Treatment chemicals react with compounds in the water to form disinfection byproducts (DBPs). Emerging chemical compound threats to health, which are not yet controlled, are called CECs. Technologies to identify CECs have recently started to improve, and are now being measured in groundwater, surface water and TSE. CECs are a threat to health throughout the world wherever humans go.  A certain degree of treatment and tests is required before TSE is injected into ASR systems. Components of the wells and aquifers should be designed to be readily accessible so that the ASR system can continue to be tested at every step of its processes. Possible threats to water purity and recovery efficiency (the percent of freshwater able to be retrieved) include surrounding rocks of multiple porosity levels with irregularities such as fissures which can make water movement unpredictable.
TSE converted to potable water is believed to be pure, but is usually avoided for the time being. Possibilities for reuse include direct potable drinking water and indirect potable reuse such as irrigation. With TSE reused as drinking water, TSE would be properly treated and then integrated into the potable water systems. Many times adding it to freshwater then breaks down harmful compounds faster. But for now, keeping systems with TSE in them physically separated from pure water systems, is the accepted practice. In Saudi Arabia, the Council of Leading Islamic Scholars agrees that TSE could be fully purified again to drink, and TSE potable water will likely go up in acceptance and even demand in the near future, especially in areas that have a dramatically dry season.
Some places are being considered for aquifer storage resource systems that incorporate TSE. In the United Arab Emirates, where conditions for underground storage are not ideal with high salinity and multiple amounts of rock porosities, ASR systems have been constructed in shallow, unconfined aquifers. The city of Abhu Dhabi is testing a site for TSE incorporation. Also in Riyadh, Saudi Arabia, the depleted Minjur aquifer is now filled with treated TSE water. Sites have also been tested in Kuwait.
Through testing of specific sites, it is likely that more ASR systems including treated TSE will emerge throughout the Middle East with the increase of water demand. Especially arid regions with population growth will be in great need of more water and TSE may become an important source. Information on the hydrogeologic conditions for proper ASR systems incorporating TSE is limited, but growing. Procuring pure water supplies from TSE is very feasible areas around the Middle East are being tested for TSE purification and storage plans. 

Controlled Water Supply and Demand Studies of England and Whales Conducted by Water Companies

In the future, climate change in England and Whales will likely cause wetter winters and dryer summers. Along with other factors, the amount of useable water available will likely decrease overall. The amount of water demanded will likely increase overall as well. Charlton and Arnell (2010) assesse the balance of supply and demand in England and Whales from 2009/2010 to 2034/35.  The estimated loss of useable water from 2009–2035 is 520 Megaliteters per day and 475 Ml/day due to climate change. Climate change is shown to likely be the largest impact on water loss with sustainability reductions, or more regulations on water taken, shown as the second largest impact. 37% of the supply-demand water stress predicted is caused by climate change. Demand increase of 620 Ml/day accounts for 56% of the pressure increase. Climate change could have such a high impact, that most companies have agreed that it must be safe guarded against and future plans must be made to access more water in the case of negative climate affects.
–Darien Martin
Charlton, M., Arnell, N. 2010., 2010. Adapting to climate change impacts
on water resources in England—an assessment of draft Water Resources
Management Plans. Global Environmental Change, Human Policy and Dimensions. 21, 238–248.

Twenty-one water companies compiled plans for 2009–2035. Data were gathered from 80 zones, compiled and analyzed to predict the amount of impact climate change would have on water supply, and to compare this magnitude to other calculated impacts. The change in demand was then calculated from 2009/10–2034/35 using 55 of the 80 zones, and compared to supply. Lastly, companies’ plans and options for future were discussed.
England and Whales have wet winters, and dryer summers, when water companies worry about having enough water supply to meet demand.  These data are compiled from 23 companies’ studies, which have been moderated economically by Oftwat, and Environmentally by an The Environmental Agency. This plan was required of each company. Each company surveyed its own resource zone and calculated the supply demand balance in its zone with the same equation: Useable output – climate change impact – sustainability reduction (or diminishing in resource use efficiency) – other reductions – other allowances – process use loss – untreated water export + untreated water import – treated water export + treated water import. Companies used this formula to determine available headroom, the amount of excess supply, which is left unused, which can recharge supplies.
          The three tasks assigned to guide companies with formulating this Water Plan were 1. Calculate river flows and levels of river when it’s replenished in different seasons; 2. Calculate future water data (by plugging groundwater data into a simulation which will predict future output); 3. Calculate future estimates of water demand; 4. Predict future headroom in wet, medium, and dry conditions. Climate change is predicted to cause hotter summers and wetter winters.
          In projections for 2034–35, climate change impact alone caused an increase in fewer than 20% of company resources zones more than 5%. The greatest impact increases were seen in the southeast of up to 15-20% in 4 zones, and 10 –15% in two zones. Small zones were impacted by climate change more generally. Other factors affected supply. The second highest impact change came from reductions of sustainable water use practices. Other affects projected were very marginal in comparison (such as water exports, process losses, and other allowances). This study also showed well that the impact of climate change in changing water supply in 2034–35 was uncertain, but that the amount of impact possible was substantial and should definitely be accounted for in companies’ future plans.
          Water supply was evaluated from present to 2035, with concern to useable output, climate change effect, sustainability reduction, outage allowance, process losses, water export, and water import. The amount of useable water was measured for three scenarios: wet, medium and dry climates. 10% loss of useable water was seen nationally. Fewer than 20% of zones had a reduction of more than 5% water supply. 58% of the water loss projected to be in the southeast of England. The total water loss predicted is equivalent to a large reservoir, holding 21,320 Ml which provides water for 1.65 million people. This poses a danger to England and Whales if they do not plan accordingly.     
In relation to this loss in water, demand is projected to increase 620 Ml/d over the 55 zones. Climate change is the dominant factor in water stress accounting for 407MI/d in these zones. A reduction in the sustainable practices required in England is the second largest impact, causing a loss of 80Ml/d in these regions. It is shown that in the case of a wetter climate scenario, some regions will have an increase in supply in the future, which could reduce the demand-supply pressure, however, this would be irrelevant, because companies would not be able to take this water.
          Possible actions for future water company plans include storage and increased connectivity. Dams would have the capacity to store excess water in the increasingly wetter wet seasons. Companies are starting to make their systems more coherent and connect their grids to flow more smoothly between zones, and correspond more directly to the networks of the water flows themselves. These connections may reduce water use losses.
Charlton and Arnell estimated that Britain would have a loss of 520MI/d of water in the next 25 years. This is 3% of overall useable water supply. The great majority of this reduction prediction will be caused by climate change.
                   In total, future water supply is projected to decrease 1117Ml/d by 2034–35 from climate change, and water companies must adapt. Companies plan to focus on water supply increase. Building more reservoirs, and connecting water systems across companies to make a more coherent grid that coincide with whole river and aquifer systems are options. Charlton and Arnell believe this would build more water resource resilience for England and Whales in dryer summers and other unforeseen circumstances. 

Evaluations and Plans for Water Resources in Distrito Federal, Brazil

Lorz et al. study of the Distrito Federal (DF) region of Brazil has found that past change in water availability has been largely due to Land use/cover change (LUCC) more so than climate change, although climate also has an effect. DF covers 5,790km2 and has a “Cerrado biome” with a savanna landscape, and dry seasons from the end of March through September. Agriculture has expanded since the 1970s. Agriculture requires high volumes of extra extractions surface and ground water, resulting in decrease of base flow discharge levels by 40–70% from the 70s. While Agriculture also affects water quality, urban development has released the most pollution into watersheds.  Water demands in DF are near their maximum capacities, and populations will likely grow along with urbanization and a resulting increase in lifestyles that demand more resources. DF, with 83% urban population is in need of an assessment for a future water plan that will limit water supply pollution, and with the recent increase in agriculture, a water system will need to obtain more water.  –Darien Martin
Lorz, C. et al. 2011. Challenges of an integrated water resource management for the
distrito federal, western central brazil: climate, land-use and water resources. Environmental Earth Science. Special issue.

Past data was used along with new studies done by Lorz et al.  for land cover/use change, climate change, and water cycling from groundwater, to surface, to resources. Lago Paranoá was evaluated as a case study of the effects of urban pollution. Twenty-one organic compounds were tracked in the lake’s water at various sites.
Fifty eight percent of the natural land was lost from 1954–1998, and additional land continues to be converted to agricultural and urban uses. Although no-tillage is practiced in DF, 90% of the agriculture is giant mechanized operations, which can contribute large amounts of fertilizer pollution into waterways, and use large amounts of water. From 2002-2007, agriculture land area increased 47%. Urban areas grew, mostly along roads, from 0.1% to 10.6% in 1954–2001.
Climate Change was studied in terms of changes in precipitation.  From data in the past from 1961–1990 and other periods projected up to 2099, dry seasons are predicted to be longer, and wet seasons, predicted to generate more rain at once. This would result in a small decrease in annual precipitation.
Groundwater and stream water supplies will be affected. Groundwater effects, in the future, will depend on the type of storage infrastructure. More porous, shallow aquifer systems have a larger danger of becoming polluted than deeper ones. Deeper aquifers. There has been a decrease in base flow discharge of streams, likely due to increased evapotranspiration of cultivated crops, increased water extraction for crops, increased water extraction for urban areas, and increased evaporation, from hard surfaces, in housing areas.
Water quality has not reached levels that are higher than regulated levels yet, but quality degradations are on the rise from sediments and organic compounds in waterways. Oxygen depletion from added organic compounds with ammonium increase near urban areas and Waste Water Treatment Effluent.
Lago Paranoá ‘s pollution levels have improved since its detrimental occurrence of eutrophication, which occurred in the 1970’s. Now, in DF, a new step has been installed in wastewater treatment, in order to remove phosphorus, but the lake is still in danger from pollution. An increased urban population has ingested and or purchased more pharmaceuticals that end up in the water.  Organic compound pollutions that don’t exceed standards now, but an increase in phosphorus concentrations is predicted. Pharmaceutical concentrations are lower than in European lakes, probably partially as a result of warm water temperatures and lots of UV radiation, which helps to degrade pharmaceutical chemicals.
It is suggested that there should be increased support for programs that continue to monitor pesticides, pharmaceuticals, sediment, and other urban pollutants in DF. In addition plans are encouraged to reclaim ruined sites, prevent erosion, and manage sediment. New technologies and green efforts will help to maintain water resources in a growing and urbanizing, Distrito Federal. 

Predicted Global Water Stress Effected by Increasing Populations, and Climate Change

Global warming and increased human population growth will affect future stresses on water resources. Vorosmarty et al. (2000) did a study predicting the effect of  human economic and population growth and the effect of global warming consequences on the amount of water demand and water supply for 2025. They found that human population and economic growth will likely cause more water stress in future than the effects of global warming. However, climate change will likely interact with increasing demand to create more water stress than would otherwise happen .–Darien Martin
Voroosmarty, C., Green, P., Salisbury, J., Lammers, R., 2000 Global water resources:
vulnerability from climate change and population growth.Science 289,  284–288.

Vorosmarty et al. evaluated sustainable water supplies, defined as runoff from rivers, above ground or in shallow aquifers, in the time frame of 1985–2025. They considered how water supplies would be affected with climate change, and collected data to determine how these effects would interact with the effects of population fluctuations and industrial development. Water stress in regions around the world were characterized as the ratio of water taken from water bodies to amount of water discharged into streams. Domestic and industrial water stress were measured separately from agricultural water stress, and both factors are also shown combined. 
          They Vorosmarty et al.  used this contemporary data to forecast water stress, climate change, increased human demand for water.
          Today, one third of the human world lives with water stress, and about 7.9% live under severe water supply stress.  Western North America, Central America, central, south South America, Central West coast of Africa, and Southern regions of Europe and Asia all have severe water stress. 
          The authors estimated that industrial and agricultural water needs, to 2025 are more affected by population and industry growth than by climate change. The population that was stressed both by population and industry growth and by climate change, was not substantially larger than the population impacted solely by population growth and industry growth alone.
          Vorosmarty et al. also collected data on the Yellow and Chin Jiang rivers to demonstrate that, conditions vary greatly even between regions in close proximity.  In a figure which shows water stress increasing  as distance from the river increases, the Yellow River population is calculated to be less stressed with climate change impact, than the Chang Jiang River population is.
          Climate change will limit water supplies in semi-arid and arid regions greatly, but population growth in cities and tropical climates is predicted to increase water stress more due to increased water pollution and demand. 

Predicted Global Water Stress Effected by Increasing Populations, and Climate Change

Global warming and increased human population growth will affect future stresses on water resources. Vorosmarty et al. (2000) did a study predicting the effect of  human economic and population growth and the effect of global warming consequences on the amount of water demand and water supply for 2025. They found that human population and economic growth will likely cause more water stress in future than the effects of global warming. However, climate change will likely interact with increasing demand to create more water stress than would otherwise happen .–Darien Martin
Voroosmarty, C., Green, P., Salisbury, J., Lammers, R., 2000 Global water resources:
vulnerability from climate change and population growth. Science 289,  284–288.

Vorosmarty et al. evaluated sustainable water supplies, defined as runoff from rivers, above ground or in shallow aquifers, in the time frame of 1985–2025. They considered how water supplies would be affected with climate change, and collected data to determine how these effects would interact with the effects of population fluctuations and industrial development. Water stress in regions around the world were characterized as the ratio of water taken from water bodies to amount of water discharged into streams. Domestic and industrial water stress were measured separately from agricultural water stress, and both factors are also shown combined. 
          They Vorosmarty et al.  used this contemporary data to forecast water stress, climate change, increased human demand for water.
          Today, one third of the human world lives with water stress, and about 7.9% live under severe water supply stress.  Western North America, Central America, central, south South America, Central West coast of Africa, and Southern regions of Europe and Asia all have severe water stress. 
          The authors estimated that industrial and agricultural water needs, to 2025 are more affected by population and industry growth than by climate change. The population that was stressed both by population and industry growth and by climate change, was not substantially larger than the population impacted solely by population growth and industry growth alone.
          Vorosmarty et al. also collected data on the Yellow and Chin Jiang rivers to demonstrate that, conditions vary greatly even between regions in close proximity.  In a figure which shows water stress increasing  as distance from the river increases, the Yellow River population is calculated to be less stressed with climate change impact, than the Chang Jiang River population is.
          Climate change will limit water supplies in semi-arid and arid regions greatly, but population growth in cities and tropical climates is predicted to increase water stress more due to increased water pollution and demand.