Spatial Analysis of Water Use in Oregon, USA, 1985–2005

Water use patterns are not distributed evenly over space and time. Determining the amount of water used within a region, as well as the various ways in which water is used is important for making adequate and sustainable water management policies and determining future water availability. We examined differences in spatial trends in Oregon freshwater use (total, municipal, and agricultural water withdrawals), by county, between the years 1985 and 2005. We also explored biophysical and socioeconomic factors that explain spatial patterns using Moran’s I, local index of spatial autocorrelation (LISA), and spatial regression models. There was a moderate positive spatial autocorrelation among counties that had similar total and irrigation withdrawals. LISA analysis identified hot spots between certain arid agricultural counties in the southeastern Oregon and cold spots between certain humid northwestern counties, including within the Portland metro area. Annual precipitation and income are negatively associated with total water withdrawals. Summer temperature and farm size is positively associated with irrigation water withdrawals, while net cash return and income are negatively associated with irrigation water withdrawals. When compared to ordinary least square regression models, spatial error models that take into account spatial dependence provide a more comprehensive explanation of the variations of water use, suggesting that water resource planning and management should incorporate spatial and neighborhood effects to effective manage limited natural resources.     

Factors influencing water level changes in China’s largest freshwater lake,Poyang Lake,in the past 50 years

This study analyses the changing characteristics in the level of Poyang Lake during the period 1960–2010. Results show that the changing stage of annual lake level variations is evident, and average onset time of the lake dry season has advanced since the 1990s. Investigation indicates that the Yangtze River discharge has a greater impact on annual lake level variations than the lake’s catchment inflow. Climate change in the Yangtze River basin since the 1990s is possibly the precondition for the advance of the lake dry season, which is further aggravated by the effects of the Three Gorges Dam in the 2000s.     

City storm-flood events in China, 1984–2015

This study uses web-based information to explore the spatial and temporal trends of reported city flood events for all mainland China cities from 1984 to 2015. Panel data were compiled on flooding (or the lack thereof) within China’s cities for every year in this period, and the relationship between the annual number of cities with reported flood events and possible influencing variables was analyzed. Few cities experienced flood events before 2001, but this situation then increased dramatically after 2010. In 2015, approximately 60% of China’s cities experienced a storm-flood event, which is three times as many as the government estimated in 2011.     

Trends in Mysis diluviana abundance in the Great Lakes, 2006–2016

With the large Diporeia declines in lakes Michigan, Huron, and Ontario, there is concern that a similar decline of Mysis diluviana related to oligotrophication and increased fish predation may occur. Mysis density and biomass were assessed from 2006 to 2016 using samples collected by the Great Lakes National Program Office's biomonitoring program in April and August in all five Great Lakes. Summer densities and biomasses were generally greater than spring values and both increased with bottom depth. There were no significant time trends during these 10–11 years in lakes Ontario, Michigan, or Huron, but there was a significant increase in Lake Superior. Density and biomass were highest in lakes Ontario and Superior, somewhat lower in Lake Michigan, and substantially lower in Lake Huron. A few Mysis were collected in eastern Lake Erie, indicating a small population in the deep basin of that lake. On average, mysids contributed 12–18% (spring-summer, Michigan), 18–14% (spring-summer, Superior), 30–13% (spring-summer, Ontario), and 3% (Huron) of the total open-water crustacean biomass. Size distributions consisted of two peaks, indicating a 2-year life cycle in all four of the deep lakes. Mysis were larger in Lake Ontario than in lakes Michigan, Superior, and Huron. Comparisons with available historic data indicated that mysid densities were higher in the 1960s–1990s (5 times higher in Huron, 2 times higher in Ontario, and around 40% higher in Michigan and Superior) than in 2006–2016.     

Water Quality Changes in Lake Erie, 1968–1980

Data on chlorophyll a, total phosphorus, and hypolimnetic dissolved oxygen concentration, which were collected by Canada Centre for Inland Waters during the period 1968 to 1980, are statistically analyzed to evaluate the changes in the water quality of Lake Erie. There are strong evidences of a decreasing trend in the value of chlorophyll a and total phosphorus in the western, central, and eastern basins of the lake between 1970 and 1980. Furthermore, a statistical model is developed for the hypolimnetic dissolved oxygen concentration in the central basin. The model shows that the increase in depletion is related to the increase in the level of total phosphorus. Hence, it is possible to improve the anoxic conditions in the lake by controlling total phosphorus loadings.     

Reservoir Sedimentation in India—Its Causes,Control, and Future Course of Action

ABSTRACT

A survey of Indian reservoirs has shown that they receive on an average about 200 percent more sediment than the design inflow. The causes are the usual, except that they are operating very intensely. In brief ‘misuse and mismanagement’ of the catchment area will describe the causes of higher rates of sedimentation.

Fortunately India is very much aware of this problem and a lot is being done by identifying the priority areas for treatment and implementation of programmes to reduce soil erosion and sediment generation.

While techniques and efficacy of various biological and structural control measures are well known, it is the policy and planning aspects which need greater attention at present. Some of them are:

—It is important that policy and planning should aim at developing the catchment area, reservoir and command area as a package.

—In the developing world sediment is the greatest pollutant and it must be recognised and treated as such.

—A policy for effective water resource and hydropower development, watershed and command area development must take into account the short term and long term, direct and indirect, private and social benefits, and endeavour to involve the people and the employees in such a way that they feel committed to efficient and effective implementation.     

Phytoplankton trends in the Great Lakes, 2001–2011

We describe recent trends in phytoplankton composition and abundance in the Laurentian Great Lakes using synoptic spring (April) and summer (August) sampling events from 2001 through 2011, a period of rapid shifts in pelagic food webs and water quality. Data analysis identified qualitative and quantitative changes in algal densities, biovolume, and taxonomic composition of assemblages. Since 2001, Lake Superior has changed subtly with an increase in small-celled blue-green algae in spring and a recent decline in summer centric diatoms, possibly a result of lake warming and changes in water quality. Spring phytoplankton declines mainly attributed to diatoms occurred in Lakes Huron and Michigan, a probable result of invasions by non-native dreissenids that have reduced pelagic nutrients and selectively consumed certain taxa. The decline in Lake Huron's spring phytoplankton biovolume was earlier and more severe than that in Lake Michigan, despite a faster and more abundant dreissenid invasion in Lake Michigan. Lake Erie's central basin had a notable increase in spring centric diatoms (largely Aulacoseira), while the whole of Lake Erie shows a summer increase in cyanobacteria, complementing that found in coastal regions. The composition of Lake Ontario's species assemblage shifted, but little overall change in algal abundance was observed with the exception of higher summer densities of cyanophytes. Additional mechanisms for shifts in the pelagic primary producers are described or hypothesized in the context of concurrent shifts in water quality and invertebrate populations. Tracking these trends and explaining driving factors will be critical to the management of lake conditions.     

Criteria for assessing the level of land–water integration in planning instruments in Andalusia,Spain

Academia has come to realize that integrating water management and land resources can deliver a significant contribution to achieving sustainable outcomes. However, its implementation in daily practice is lagging behind. In order to address this knowledge–practice gap, this paper suggests the integration of land and water resources management can be improved through the incorporation of specific criteria in the territorial plans and river basin management plans. The proposed criteria were used to develop a methodology to assess the level of integration between water resources and land uses in current planning practice. The case of Andalusia in Spain provided the empirical focus.     

Hydel Power Development Issues, Counter Measures and Policies in Pakistan

1. Barriers ＆ Mitigation to Commercialization of Small Hydel Power Plants In Pakistan 1.1 Institutional Barriers In Pakistan, research, development and implementation of small ＆ micro hydel power on commercial scale has been hampered by a lack of cordination, institutional support, poor definition of mandates and responsibilities of the organizations. Until May, 2003, there was not a single central agency with the overall responsibility for policy, planning, targets, co-ordination and strategic management of this sector, although there were a number of disparate bodies set up with limited objectives and little coordination amongst different stakeholder.     

Sediment Lead Loads in the Niagara River, 1986–1992

The problem of estimating sediment lead loads from Lake Erie to the Niagara River and from the river to Lake Ontario is considered. Using weekly data for the period 8 May 1986 to 12 October 1992, autoregressive time series models containing terms for trend and seasonality were developed for the average daily load at the head (FE) and mouth (NOTL) of the river, as well as for the load ratio and difference between the two sites. The estimated average load at the Fort Erie station decreased dramatically from 230 kg/day in 1986 to a roughly constant level of approximately 87 kg/day thereafter, the lowest value of 74 kg/day being reached in 1992. At the Niagara-on-the-Lake station, daily load declined gradually throughout the measurement period, from 110 kg/day in 1986 to 65 kg/day in 1992. Thus, by 1992, there was little difference (9 kg/day) in the loads at the two sites, suggesting that the major contribution of sediment lead to the Niagara River was from Lake Erie.     

Studies of Large-Scale Currents in Lake Erie, 1979–80

Currents and water temperatures were recorded at a large-scale grid of fixed moorings in Lake Erie from May 1979 through June 1980. Currents measured in the lower half of the central basin water column were mostly return flows (beneath the surface wind drift) driven by the surface pressure gradient. Often observed was a complex system of Lake Erie circulation gyres as predicted by models. Another common occurrence was for one of the central basin gyres to become dominant and envelop the whole basin in either uniform clockwise or anticlockwise flow. It is not fully certain why one of the circulation cells grows as opposed to the others, but the curl of the wind stress had influence. The currents were more barotropic than predicted by full Ekman layer current models. Tidal-like currents driven by the longitudinal seiches of Lake Erie dominate the island-filled passages between the western and central Lake Erie basins, with currents across the whole island chain very closely in phase. Processes of hypolimnion volume entrainment are suggested from the central basin temperature recordings. Large volume water exchanges between the central and eastern basins occurred after the water mass in the vicinity of the shallow ridge that separates them had become unstratified. These and other topics are discussed as the large data set generated from the experiment is explored.     

Study of Drawdown–Drain Discharge Relationship and its Application in Design of Cost Effective Subsurface Drainage System in Mugogo Swamp, Busogo, Rwanda

Mostly the swamps in Rwanda are surrounded by volcanic hills with small streams flowing to discharge runoff and seepage water. Mugogo swamp is located in Busogo sector, Musanze district, North province. Total area of the swamp is approximately 50 ha. The swamp is surrounded by hills and elevated volcanic rocky terrains. Potato is the main crop cultivated in the swamp. The average production rate of potato is 7 MT/ha which is very low compared to 12 MT/ha in well drained areas. During rainy season seepage water and runoff water from the surrounding hills cause the waterlogged condition of the swamp and affecting the potato cultivation and land productivity. The remedial measure for this swamp is to divert separately the runoff and seepage water from surrounding catchment area and then remove the recharge water by pumping through a system of subsurface drains. Hydraulic head–drain discharge relationship can be fitted with quadratic equation. Equivalent drainable porosity and equivalent hydraulic conductivity are determined as 0.105 m/day and 0.34% respectively for drain depth of 40 cm from soil surface. Effective hydraulic conductivity in the soil profile shows that its average value in the top 15 cm of soil layer is 0.17 m/day and that in the remaining depth up to impermeable layer is 0.015 m/day. Third degree polynomial expressions are made for Head–hydraulic conductivity and head–drainable porosity relationships. The nonlinear relation of hydraulic conductivity and drainable porosity with drawdown shows that the proximity of Kinoni stream does not affect drainage parameters of the area because of less seepage from the stream. The study also reveals that adoption of 7 m drain spacing is very less if crop parameter is not considered and will result higher drain cost. Drainage coefficient of 5 mm/day is arrived considering the rainfall distribution, infiltration rate of soil, allowable water logging tolerance of potato crop. Required drain spacings are calculated for different drainage coefficients of 1, 2, 3, 4 and 5 mm/day under different drawdown conditions to plot subsurface drainage characteristic curves of the swamp. These curves are useful to directly read the drain spacing and drain depth for the required drainage coefficient without going for tedious calculations. Cost analysis shows that the ratio of drain spacing to drain depth can be a decisive factor to select best combination of drain depth and drain spacing. For drainage coefficient of 5 mm/day, optimum drain spacing-depth ratio is found as 7.2 with a cost of 0.689 million Frw/ha. For different drainage coefficients in the swamp, the drain depth of 1.5 m is crucial and optimum cost occurs at this depth. It is also found that any increase in drawdown beyond the drawdown at critical drain depth will not reduce the cost significantly.     

Trends in the distribution and abundance of Hexagenia spp. in Saginaw Bay,Lake Huron, 1954–2012: Moving towards recovery?

Since at least the 1940s, multiple anthropogenic disturbances to the Laurentian Great Lakes have had detrimental effects on benthic habitats and biota including decimating the environmentally sensitive burrowing mayfly genus Hexagenia around the mid-1950s. While remediation efforts have facilitated recovery of some populations, benthic surveys in Saginaw Bay, Lake Huron in the last 50 years have only occasionally discovered Hexagenia nymphs. Recently, adult Hexagenia swarms have been reported near the bay; therefore, we corroborated the local presence of Hexagenia adults and evaluated the current status of Saginaw Bay Hexagenia nymphs. We quantified adults during mayfly emergence events in 2010 at three Tawas City, Michigan, USA area locations, and found > 17 Hexagenia/m²/site. We quantified nymphs from Ponar grab samples collected at 57 sites in Saginaw Bay between 2009 and 2012, and found 1.5 nymphs/m² overall with nymphs present at 15.8% of sites sampled, their greatest documented distribution in Saginaw Bay since 1956. Additionally, we mapped bay sediment composition and related sampling site abiotic conditions with both Hexagenia presence and abundance using Zero-Inflated Poisson regression. Model results indicate that the probability of observed Hexagenia absence being true absence is positively related to both sediment sandiness and surficial dissolved oxygen concentration while Hexagenia abundance is greatest where surficial temperatures are ~ 18.6 °C and is also related to sediment sand content. The documentation of nearby adults and in bay nymphs may indicate the beginning of a Hexagenia return to Saginaw Bay, and, therefore, a possible improvement of the ecosystem's benthic health.     

Abundance and distribution of benthic macroinvertebrates in offshore soft sediments in Western Lake Huron, 2001–2007

Invasive species have had major impacts on the Great Lakes. This is especially true of exotic dreissenid mussels which are associated with decreased abundance of native macroinvertebrates and changes in food availability for fish. Beginning in 2001, we added a benthic macroinvertebrate survey to the USGS-Great Lakes Science Center's annual fall prey fish assessment of Lake Huron to monitor abundance of macrobenthos. Mean abundance of Diporeia, the most abundant benthic taxon in Lake Huron reported by previous investigators, declined greatly between 2001 and 2007. Diporeia was virtually absent at 27-m sites by 2001, decreased and was lost completely from 46-m depths by 2006, but remained present at reduced densities at 73-m sites. Dreissenids in our samples were almost entirely quagga mussels Dreissena bugensis. Zebra mussels Dreissena polymorpha were virtually absent from our samples, suggesting that they were confined to nearshore areas shallower than we sampled. Loss of Diporeia at individual sites was associated with arrival of quagga mussels, even when mussel densities were low. Quagga mussel density peaked during 2002, then decreased thereafter. During the study quagga mussels became established at most 46-m sites, but remained rare at 73-m sites. Length frequency distributions suggest that initial widespread recruitment may have occurred during 2001–2002. Like other Great Lakes, Lake Huron quagga mussels were associated with decreased abundance of native taxa, but negative effects occurred even though dreissenid densities were much lower. Dreissenid effects may extend well into deep oligotrophic habitats of Lake Huron.     

Urban Rainwater Utilization and its Role in Mitigating Urban Waterlogging Problems—A Case Study in Nanjing, China

With the acceleration of the urbanization process, urban waterlogging problems are becoming more and more serious in Nanjing, China. In order to mitigate the urban waterlogging problems, it is necessary to reduce surface runoff from the source by rainwater harvesting and utilization. An urban residential district with an area of 0.58?km² in Nanjing was selected as the study area. Based on a large-scale topographic map data and the long term rainfall data (1951?C2008), the types of underlying surfaces were classified. The potentiality of collectable rainwater and the possibility of runoff volume reduction were calculated. The results showed that exploitation of rainwater harvesting from rooftops and other underlying surfaces has high potential. The annual collectable rainwater is approximately 372,284?m³, 314,034?m³ and 275,180?m³ under different cumulative frequency of rainfall at 20?%, 50?% and 75?%, respectively. The total capacity of cisterns under assumptions of return period of rainfall and rainfall duration with 5?years and 20?min is 11,022?m³. The cistern??s capacity which is used for roof rainwater harvesting is 4,083?m³, the cistern capacity for per unit roof area (1?m²) is 0.0267?m³. The results of the feasibility analysis of setting up above-ground cisterns showed that 55?% of the total roof areas in the study area are available for setting up cisterns. In the three building types, 16?% of the commercial building??s roof areas and 77?% of that of the residential and the ??others?? buildings are available for setting up cisterns. Urban waterlogging problems can be effectively reduced through rainwater harvesting by 13.9?%, 30.2?% and 57.7?% of runoff volume reduction in three cases of the maximum daily rainfall (207.2?mm), the average annual maximum daily rainfall (95.5?mm) and the critical rainfall of rainstorm (50?mm).     

Tributary contributions to sediment deposited in the Jacuí Delta,Southern Brazil

The Jacuí Delta drains into Lake Guaíba which is the main source of water for more than two million people in South Brazil and has suffered from pollution with heavy metals and phosphorus. The objective of the current research is to demonstrate how the use of sediment source tracing techniques, in combination with sediment flux monitoring, can improve understanding of the sediment source contributions to one of the largest lakes in South America. The sediment flux monitoring results were based on data obtained from 12-years of records of water flow and suspended sediment concentrations. The sediment source fingerprinting approach was based on the use of geochemical tracers. Based on the study, the respective contributions of the tributaries to the sediment in Lake Guaíba were estimated to be as follows: the Jacuí River (median of 54% - interquartile range (IQR) 34–71%), the Caí River (12%, IQR 7–16%), the Sinos River (5%, IQR 1–20%), and the Gravataí River (16%, IQR 10–30%). These results are similar to those derived from the sediment flux monitoring, namely: the Jacuí River (70%), the Caí River (19%), the Gravataí River (4%), and the Sinos River (7%). These results demonstrate that the sediment source fingerprinting approach combined with sediment flux monitoring can provide a useful means of estimating the respective sediment contributions from individual tributaries in large and complex delta systems and may provide a powerful tool to guide water resource management.     

Dynamics of fecal indicator bacteria,bacterial pathogen genes,and organic wastewater contaminants in the Little Calumet River–Portage Burns Waterway,Indiana

Little information exists on the co-occurrence of fecal indicator bacteria (FIB), bacterial pathogens, and organic wastewater-associated chemicals (OWCs) within Great Lakes tributaries. Fifteen watershed sites and one beach site adjacent to the Little Calumet River–Portage Burns Waterway (LCRPBW) on Lake Michigan were tested on four dates for pH, dissolved oxygen, specific conductance, chloride, color, ammonia- and nitrate-nitrogen, soluble phosphorus, sulfate, turbidity, and atrazine; for concentrations of FIB; and for genes indicating the presence of human-pathogenic enterococci (ENT) and of Shiga-toxin producing Escherichia coli (EC) from various animal sources. Nineteen samples were also tested for 60 OWCs. Half of the watershed samples met EC recreational water quality standards; none met ENT standards. Human-wastewater-associated OWC detections were correlated with human-influence indicators such as population/km², chloride concentrations, and the presence of WWTP effluents, but EC and ENT concentrations were not. Bacterial pathogen genes indicated rural human and several potential animal sources. OWCs of human or ecosystem health concern (musk fragrances AHTN and HHCB, alkylphenols, carbamazepine) and 3 bacterial pathogen genes were detected at the mouth of the LCRPBW, but no such OWCs and only 1 pathogen gene were detected at the beach. The LCRPBW has significant potential to deliver FIB, potential bacterial pathogens, and OWCs of human or ecosystem health concern to the nearshore of Lake Michigan, under conditions enhancing nearshore transport of the river plume. Nearshore mixing of lake and river water, and the lack of relationship between OWCs and FIB or pathogen genes, pose numerous challenges for watershed and nearshore assessment and remediation.     

Firms’ willingness to invest in a water fund to improve water-related ecosystem services in the Lake Naivasha basin,Kenya

A valuation scenario was designed using a contingent-valuation approach and presented to decision makers in business firms in Kenya’s Lake Naivasha basin to test how applicable a water fund might be as a potential financing mechanism for a payment for water-related ecosystem services scheme. The findings indicate that measuring a firm’s willingness to invest in ecosystem services could help determine whether a firm would invest and engage with other stakeholders to pool their investments in ecosystem services. Linking the institutional decision-making behaviour of a firm and its willingness to invest in a water fund is the novelty of this article.     

When free-riders become the agents for change—migrant fishers,institutional resilience,and adaptive fisheries management in Malawi

Fisheries co-management in Malawi has not achieved the successes anticipated. Mobility of fisherfolk is frequently blamed for the poor effectiveness of local institutions, and this often leads to calls for access limitation. However, recent research in Malawian water bodies suggests that fisher mobility increases livelihood sustainability for all lakeshore residents involved, and is well adapted to these contexts of fluctuating and uncertain fisheries. Therefore, the abilities of fisherfolk to move into and out of different local fisheries can arguably be judged to enhance fisheries resilience overall. In addition to these benefits, we present data from two ethnographic case studies to illustrate the positive impacts that migration has had on some of Malawi's more successful fisheries co-management institutions (known as Beach Village Committees or BVCs).Despite preexisting concerns regarding unsustainable local fishing practices, local stakeholders were unwilling or unable to address these challenges until conflicts with migrant fisherfolk prompted changes. In some cases, the ability of migrants to circumvent BVC regulations has highlighted the BVC's lack of local legitimacy. Additionally, when threatened with losing benefits to “outsiders,” local stakeholders are more willing and able to come together and take corrective action. We therefore argue against policies limiting access to local fisheries as these remove valuable catalysts for adaptive institutional learning in decentralized natural resources management.