The deflectors influence on flow complexity,bed morphology,sediment transport and water quality of urban lotic waters - A laboratory study

In this laboratory study different combinations of bed (sand, pebble gravel [gravel], and a mix of sand and gravel) and flow (typical and overtopping) were experimented with to investigate the impact of porous deflectors in flow diversity, water quality, and fish performance in prismatic open channels. Deflectors changed the gradually varied flow to a rapidly varied flow, as a sudden change in the water depth was observed at the deflectors, and this change was large for smooth beds. With the presence of gravel, the scouring near the downstream deflector was almost twice that of the sand bed, and with the scouring at its own upstream deflector, irrespective of whether the flow was typical or overtopping. This behavior was a result of sand mobilization due to shear stress and sand mobilization aided gravel transport. The mixed bed showed less gravel movement compared to the gravel-only bed. The percentage of sediment washed out was minor for all bed scenarios, indicating that sediment transport was local. Relative to the sand bed without deflectors (representing a typical urban canal), deflectors resulted in reduced and improved water quality (in terms of sediment load) for sand, and mixed bed, respectively. The fishes found refuge and were comfortable in the pool areas created by deflectors unlike in channels without deflectors where they showed exhaustion.     

Temporal trends in agricultural water use and the relationships to hydroclimatic factors in the High Plains aquifer region

The High Plains aquifer (HPA) is the primary water source for agricultural irrigation in the US Great Plains. The water levels in many locations of the aquifer have declined steadily over the past several decades because the rate of water withdrawals exceeds recharge, which has been a serious concern to the water resources management in the region. We evaluated temporal trends and variations in agricultural water use and hydroclimatic variables including precipitation, air temperature, reference evapotranspiration, runoff, groundwater level, and terrestrial water storage across the HPA region for different periods from 1985 to 2020 at the grid, county, or region scale. The results showed that water withdrawals decreased from 21.3 km³/year in 1985 to 18.2 km³/year in 2015, while irrigated croplands increased from 71,928 km² in 1985 to 78,464 km² in 2015 in the entire HPA. The hydroclimatic time-series showed wetting trends in most of the northern HPA, but drying and warming trends in the southern region from 1985 to 2020. The groundwater level time-series indicated flat trends in the north, but significant declining in the central and southern HPA. Trends in irrigation water withdrawals and irrigation area across the HPA were controlled by the advancement of irrigation systems and technologies and the management of sustainable water use, but also were affected by dynamical changes in the hydroclimatic conditions.     

Factors influencing property selection for conservation revolving funds

Finding sustainable ways to increase the amount of private land protected for biodiversity is challenging for many conservation organizations. In some countries, organizations use revolving‐fund programs, whereby land is purchased and then sold to conservation‐minded owners under condition they enter into a conservation covenant or easement. The sale proceeds are used to purchase, protect, and sell additional properties, incrementally increasing the amount of protected private land. Because the effectiveness of this approach relies on selecting appropriate properties, we explored factors currently considered by practitioners and how these are integrated into decision making. We conducted exploratory, semistructured interviews with managers from each of the 5 major revolving funds in Australia. Responses indicated although conservation factors are important, financial and social factors are also highly influential. A major determinant was whether the property could be resold within a reasonable period at a price that replenishes the fund. To facilitate resale, often selected properties include the potential for the construction of a dwelling. Practitioners face with clear trade‐offs between conservation, financial, amenity, and other factors in selecting properties and 3 main challenges: recovering the costs of acquisition, protection, and resale; reselling the property; and meeting conservation goals. Our findings suggest the complexity of these decisions may constrain revolving‐fund effectiveness. Drawing from participant responses, we identified potential strategies to mitigate these risks, such as providing adequate recreational space without jeopardizing ecological assets. We suggest managers could benefit from a shared‐learning and adaptive approach to property selection given the commonalities between programs. Understanding how practitioners deal with complex decisions in the implementation of revolving funds helps identify future research to improve the performance of this conservation tool.     

A climate-change vulnerability and adaptation assessment for Brazil's protected areas

Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km²) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km²), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future.     

可拓优度评价法在城市区域消防安全评价中的应用

为了解决城市区域消防安全评价的复杂性和不确定性,本文运用可拓优度评价法,根据相关文件并结合城市区域消防的实际情况,从火灾危险程度、城市区域特征、消防实力水平和社会管理状态4个方面选取17个指标,建立了城市区域消防安全评价指标体系并划分了消防安全等级,以洛阳市西工区为例对城市区域消防安全评价的可拓优度方法进行了验证。结果表明,可拓优度方法可以准确反映出该区域消防安全水平。     

南京市农用地土壤中重金属形态特征分析

以南京市农用地土壤为研究对象,采用顺序提取的方法对Cu、Zn、Pb、Cd做化学形态分析,了解不同元素各形态下空间赋存的含量与占比。结果表明,在农用地土壤中,上述4种金属元素所赋存的化学形态活泼性顺序为CdPbCuZn,其中Cd主要为醋酸提取态,Pb主要为可还原态,各占总量的40%以上,具有较高的生物有效性和潜在危害性;Cu与Zn主要为残渣态,占总量的60%左右,生物可利用性较低。由因子分析法可知,土壤p H值越大,Zn与Cd就越趋于向稳定的化学形态转化,土壤有机质含量越高,对Cu与Pb的络合能力就越强,可以降低其环境危害性。     

基于Landsat 8遥感数据的天津市地表温度反演

以Landsat 8遥感数据为数据源,进行天津市地表温度反演研究。首先采用单通道算法反演地表温度,并利用均值标准差法进行温度分级。然后建立不同温度等级面积比例的估算模型。再通过随机样点,从不同温度等级和土地覆盖类型2个角度,分别建立并比较不同类样点的地表温度与各指数的拟合模型。结果表明:次高温区域面积比例与人口密度、人均GDP都具有较高的决定系数;地表温度与NDVI、BAEM的二元线性回归决定系数高于地表温度与单一指数的决定系数;将样点分类后,低温点与MNDBI的决定系数高于其他温度等级样点,水域和植被样点与各种指数的决定系数高于其他地物类型样点。     

Who shapes local climate policy? Unpicking governance arrangements in English and German cities

A new framework for analysing subnational policymaking is applied to climate governance in the ‘twin towns’ of Newcastle upon Tyne and Gelsenkirchen. Low levels of resource interdependence between central and local government in England mean that Newcastle Council has to rely heavily on other horizontal actors to achieve its climate objectives. In contrast, Gelsenkirchen Council receives substantial support from higher tiers of government, which gives it greater control over policymaking within the locality. Greater independence between tiers of government can make it more difficult for subnational bodies to adopt the kind of ambitious policies that may be necessary to combat wicked and/or significant policy challenges such as climate change. Instead, interdependent ‘joint-decision’ systems, which facilitate mutual support across tiers of government, may be better equipped to ensure that subnational public bodies have the capacity to act appropriately.     

Considering climate change and regional differences: An efficiency assessment of coal mine use and land restoration

China is the country with the largest coal mining production and consumption in the world, but due to a large amount of coal burning, air pollution and climate change are exasperating related problems. The previous literature mainly has discussed coal mine production and environmental pollution, but failed to take into account external factors such as climate change and seldom discussed the relationship between coal mine land use and land restoration. Therefore, this study uses the meta-Epsilon-Based Measure two-stage Data Envelopment Analysis under the exogenous model and incorporates coal mine land use and land restoration use into the model to explore the relationship between the two under climate change. The research results are as follows. (1) If the external climate factors are not considered, then the phenomenon of overestimation or underestimation of the technology gap arises. (2) The efficiency value of the coal mining stage in most provinces is generally higher than the land restoration efficiency value.     

Oil dependency,political institutions,and urban–rural disparities in access to electricity in Africa

In line with the resource curse literature, this paper examines the effect of oil dependency on the disparities in access to electricity between urban and rural areas in Africa, conditional on the quality of political institutions. Based on data from 36 African countries over the period 2000–2017, our investigation suggests that oil rents (% of GDP) increase urban–rural disparities in access to electricity. However, the quality of institutions shapes the effect of oil dependency on these disparities. Specifically, a 10% increase in the institutional quality score reduces the adverse effects of oil rent on electricity access disparity by around 19%, and the negative impact of oil dependency on urban–rural disparities is reversed when institutional quality reaches a score of 52% on a scale from 0 to 100. The robustness tests support these results and call for strengthening the quality of institutions to overcome the resource curse in Africa.