Quality of urban runoff in wet and dry seasons: a case study in a semi-arid zone

Land cover mapping by optical remote sensing has many obstacles including clouds. Clouds block solar radiation coming to earth surface and reflective radiance from the earth surface to remote optical sensors resulting. Therefore, clouds result no-signal areas in images that cannot be used for study of ground objects. In many cases, thin clouds degrade quality of reflective radiance and some times alter, unexpectedly, spectral reflectance characteristics of ground objects leading to false classification. In this paper, the authors present an algorithm on application of multidate for development of cloud free image. The used image data were received in rainy and dry seasons and by stacking, cloud free images representing rainy and dry seasons were created. These cloud free images can be used further for classification of land cover in rainy and dry seasons. Experiments were conducted with Landsat 8 OLI images with path/row number 124/51 covering Dak Lak province of Vietnam. The results of case study were development of cloud free image data representing rainy and dry seasons allowing separation of evegreen and deciduous forests in the study site.

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Tillage-induced wind erosion in semi-arid fallow lands of Central Anatolia, Turkey

Soil and Water Research ◽

10.17221/73/2016-swr ◽

2017 ◽

Vol 12 (No. 3) ◽

pp. 144-151 ◽

Cited By ~ 1

Author(s):

M. Başaran ◽

O. Uzun ◽

S. Kaplan ◽

F. Görmez ◽

G. Erpul

Keyword(s):

Mass Transport ◽

Wind Erosion ◽

Soil Characteristics ◽

Sediment Flux ◽

Agricultural Activity ◽

Conventional Agriculture ◽

Fallow Lands ◽

Dry Seasons ◽

Semi Arid ◽

Wet And Dry Seasons

Wind erosion and resultant dust emissions create significant risks for land degradation and ecosystem health in arid and semi-arid regions. In these regions, fallowing constitutes a major component of conventional agriculture. The present study was conducted to determine wind erosion quantities and agricultural activity-induced mass transport from fallow lands and to assess the correlations of mass transport with climate and soil characteristics. Experiments were conducted over the fallow lands of two adjacent agricultural enterprises (Altinova and Gözlü, Turkey). Sediment flux was measured with passive traps in wet and dry seasons (QtWET and QtDRY). Mass transport in wet and dry seasons was respectively measured as 11.38 and 11.40 kg/ha in Altinova and as 31.61 and 19.71 kg/ha in Gözlü. Both the differences between mass transport of the enterprises and the differences between QtWET and QtDRY of each enterprise were found to be significant (P < 0.05). Pearson’s correlation analysis for the correlations of mass transport with soil characteristics revealed significant correlations with electrical conductivity and soil lime content (r = 0.721 and –0.635) (P < 0.05). Total mass transport from the fallow lands of both enterprises throughout a 7-month period of measurement was estimated at 600 t. Based on current findings it was concluded that fallowing should be abandoned and sustainable soil and land management practices from conventional agriculture like minimum tillage or crop rotations should be introduced.

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Seasonal Changes and Spatial Variation in Water Quality of a Large Young Tropical Reservoir and Its Downstream River

Journal of Chemistry ◽

10.1155/2017/8153246 ◽

2017 ◽

Vol 2017 ◽

pp. 1-16 ◽

Cited By ~ 10

Author(s):

Teck-Yee Ling ◽

Norliza Gerunsin ◽

Chen-Lin Soo ◽

Lee Nyanti ◽

Siong-Fong Sim ◽

...

Keyword(s):

Water Quality ◽

Aquatic Organisms ◽

Organic Pollution ◽

Wet Season ◽

Tropical Reservoir ◽

Different Depths ◽

Dry Seasons ◽

Water Quality Deterioration ◽

Wet And Dry Seasons

This study examined the water quality of the large young tropical Bakun hydroelectric reservoir in Sarawak, Malaysia, and the influence of the outflow on the downstream river during wet and dry seasons. Water quality was determined at five stations in the reservoir at three different depths and one downstream station. The results show that seasons impacted the water quality of the Bakun Reservoir, particularly in the deeper water column. Significantly lower turbidity, SRP, and TP were found during the wet season. At 3–6 m, the oxygen content fell below 5 mg/L and hypoxia was also recorded. Low NO2--N, NO3--N, and SRP and high BOD5, OKN, and TP were observed in the reservoir indicating organic pollution. Active logging activities and the dam construction upstream resulted in water quality deterioration. The outflow decreased the temperature, DO, and pH and increased the turbidity and TSS downstream. Elevated organic matter and nutrients downstream are attributable to domestic discharge along the river. This study shows that the downstream river was affected by the discharge through the turbines, the spillway operations, and domestic waste. Therefore, all these factors should be taken into consideration in the downstream river management for the health of the aquatic organisms.

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Improving management of rice in semi-arid eastern Indonesia: responses to irrigation, plant type and nitrogen

Australian Journal of Experimental Agriculture ◽

10.1071/ea98032 ◽

1998 ◽

Vol 38 (3) ◽

pp. 261 ◽

Cited By ~ 7

Author(s):

A. K. Borrell ◽

R. M. Kelly ◽

D. E. Van Cooten

Keyword(s):

External Input ◽

Rice Production ◽

Saturated Soil ◽

Wet Season ◽

Soil Culture ◽

Dry Seasons ◽

Low External Input ◽

West Timor ◽

Semi Arid ◽

Wet And Dry Seasons

Summary. A number of field experiments were undertaken in eastern Indonesia with the aim of improving rice production in this semi-arid region. The objectives of these studies were to examine the effects of irrigation method (raised beds under saturated soil culture v. flooded system), irrigation frequency (daily v. twice weekly) and genotype (traditional v. improved) on rice yield and components of yield, and to examine the response of rice growth on raised beds to sowing time and nitrogen fertilisation. Recent studies in northern Australia have demonstrated that rice can successfully be grown under saturated soil culture. In the Australian studies, grain yield and quality were maintained, yet saturated soil culture used 32% less water than the flooded control in both wet and dry seasons. Higher efficiencies of water use for rice production with saturated soil culture in semi-arid tropical Australia suggest that similar benefits may be realised with this method of irrigation in West Timor. The experiments in West Timor were undertaken within a low-external-input system, and all experiments were affected by drought. The central issue is one of aligning crop growth with water availability to ensure adequate quantity and quality of grain production at the end of the season. On this basis, a number of practical strategies for improving rice production under water-limited conditions in West Timor are suggested. First, time of sowing in the wet season is important, with early-sown crops escaping end-of-season drought. Significantly, the improved genotype (cv. Lemont) was only able to fill its grain adequately if sown early in the wet season, thereby avoiding drought during grain filling. Second, providing soils are sufficiently deep, rice can successfully be grown under saturated soil culture in West Timor. Importantly, preparation of raised beds before the wet season enables rice crops to be sown early, maximising the use of rainfall for crop production. Twice weekly irrigation of rice on beds was found to be more efficient than irrigating daily or flooding the bays. Third, no differences in grain yield were found between the improved short-statured genotype (cv. Lemont) and the taller traditional genotype under the low-external-input system, although differences in components of yield were observed in the wet and dry seasons. There is some evidence that the traditional genotype filled grain better when water was limiting during grain growth by restricting vegetative production and enabling the crop to finish.

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The effect of seasonal climate on bottled water distribution in rural Cambodia

Water Science & Technology Water Supply ◽

10.2166/ws.2013.063 ◽

2013 ◽

Vol 13 (3) ◽

pp. 798-807

Author(s):

D. White ◽

C. A. Hutchens ◽

P. Byars ◽

B. Antizar-Ladislao

Keyword(s):

Water Distribution ◽

Historical Data ◽

Household Wealth ◽

Bottled Water ◽

Common Source ◽

Safe Drinking Water ◽

Seasonal Climate ◽

Dry Seasons ◽

Wet And Dry Seasons

The rural population of Cambodia currently has limited access to improved water sources, with monthly access significantly varying between the wet and dry seasons. This poses difficulties for many households across the country, especially in the dry season when stored rainwater – a common source for many – becomes difficult to obtain, necessitating a switch to sources unsafe for consumption. This study evaluates the effect of seasonal climate on bottled water as an alternative solution to accessing safe drinking water. A study of 240 households in the Battambang province, Cambodia correlated seasonal uptake of bottled water with household wealth, quality of road access and access to alternatives. This was supported by historical data on bottled water uptake from three communities. The results suggest that substantial seasonal change in uptake occurs in rural Cambodia; most noticeably in households of low wealth. As one of the first studies on bottled water in Cambodia, these are important findings; particularly given the recent increase in rural bottled water distribution. The study finds bottled water is not an appropriate means for Non-Governmental Organisations targeting the poorest strata of the community; however there is potential for the private sector to supply more affluent households.

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Physical–chemical evaluation of groundwater quality in semi-arid areas: case study—Sabzevar plain, Iran

Sustainable Water Resources Management ◽

10.1007/s40899-021-00576-y ◽

2021 ◽

Vol 7 (6) ◽

Author(s):

Ghasem Panahi ◽

Mahya Hassanzadeh Eskafi ◽

Hamidreza Rahimi ◽

Alireza Faridhosseini ◽

Xiaonan Tang

Keyword(s):

Water Resources ◽

Groundwater Quality ◽

High Salinity ◽

Groundwater Resources ◽

Arid Areas ◽

Agricultural Use ◽

Anions And Cations ◽

Semi Arid

AbstractGroundwater is one of the most important water sources in arid and semi-arid areas. With the increasing world population and the water demand for agriculture and urban use, the need for water resources has increased, especially in arid and semi-arid regions, where groundwater resources play a significant role. To prevent the pollution of groundwater resources, various studies for their preservation and maintenance should be carried out, including a detailed plan for proper management of water resources and establishing a balance between water quality and how to use them. It becomes important to understand the spatial change of the quality of groundwater resources. In this study, Sabzevar plain, a typical region of semi-arid climate in Iran, was selected as a case study to assess the groundwater quality of the region, using data from 24 observation wells between 2015 and 2019. Using Arc GIS software, a map of groundwater quality parameters in the study area was prepared for quality assessment and comparison with existing international standards. The results showed that (except pH and HCO3−) the concentration of Sodium, Magnesium, and other anions and cations is higher than the corresponding WHO standard limit, suggesting that the study area is unsuitable for drinking and agricultural use. According to the Wilcox chart, 87.5% of the samples are in the C4S4 class while 8.33% are in the C4S3 class, showing the groundwater unsuitable for agricultural use due to its high salinity and alkalinity. Piper diagrams show that more than 50% of the samples are non-carbonate alkalis, indicating a very high salinity in the area. According to the pie chart, chlorine ion and sodium ion are the dominant anions and cations in the Sabzevar plain, respectively. The Schuler diagram shows that none of the samples examined were in a good class for drinking. Therefore, considering the importance of water for agricultural activities in the study area, it is recommended to have agricultural management solutions to prevent groundwater mixing with freshwater resources.

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Three-Fold Remedial Measures for Groundwater Protection: Case Study of the Khathkari Stream, Pune District, India

Water Science & Technology ◽

10.2166/wst.1991.0334 ◽

1991 ◽

Vol 24 (11) ◽

pp. 33-40

Author(s):

Nasrollah Kalantari ◽

S. S. Thigale

Keyword(s):

Groundwater Protection ◽

Integrated Approach ◽

Remedial Measures ◽

Paper Briefly ◽

Quality Of Water ◽

Hydrochemical Studies ◽

Low Precipitation ◽

Semi Arid

A vast tract in Maharashtra State of India, constituted of horizontally disposed basaltic flows of Cretaceous-Eocene age, falls in the semi-arid climatic zone characterised by low precipitation and high temperature and evaporation. Such areas are marked by the variety of calcretes including massive, honeycomb, nodular, and powdery types. These calcretes which owe their origin to both pedogenic and nonpedogenic processes, are responsible for imparting the salinity to the groundwater. An integrated approach, involving geological, hydrogeological and hydrochemical studies, has been employed for delineating the boundary of saline and fresh waters in the groundwater system and evaluating the variation in salinity in the area around the Khathkari stream (18 13’ to 18 18’ N latitudes, and 74 13’ to 74 22’E longitudes) in Pune district. The paper briefly presents the data collected during the course of the work and incorporates the three-fold remedial measures such as i) protecting fresh water that occurs at deeper depth, ii) improving the present quality of water and iii) suggesting an appropriate crop-pattern that can stand for present and improved quality of water.

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