Background and objectives of the study
Climate change is leading to enhanced uncertainty, increased variability and intensive shortage of water resources. Thus new challenges are arising for water resources management regarding water institutions and management mechanisms, even in such areas that traditionally have not been afflicted with water scarcity and related stresses. Water institutions are composed of water law, policy, and administration. Institutional changes within the water sector occur due to the influence of both endogenous and exogenous factors.
Our fundamental investigation involves the way in which adequate and optimal policies might facilitate designing and development of water institutions under climate change. As discussed below, we focus on the different roles of actors involved, past and current institutions, and property right regimes. We look at climate change and induced variability of water resources as a source of agricultural production and welfare variability, which can further result in variability of incentives to managing and applying water resources to better adapt to climate change.
Three major water doctrines in U.S. and comparison in five representative states
There are three major water allocation doctrines existing in U.S. Roughly separated by Kansas City, riparian doctrine dominated most of eastern states, including Illinois and Missouri. Riparian rights are obtained based on ownership of riparian land, bordering or underlying watercourses or covering groundwater aquifer. In contrast, prior appropriation doctrine prevails 18 western states, for instance, Nebraska and Kansas, and establishes the principle of “first in time, first in right”, that is, the first user has a senior right to water resources. In past 60 year, 17 eastern states, e.g., Iowa, have adopted regulated riparianism to manage allocation of water resources and permits need to be obtained to practice the reasonable use of water resources.
Institution designing for water management and policy implications
Institution designing for multilayer water management should be focusing on three aspects. 1) Political intervention needs to emphasize lower transaction costs policy options, transferable and flexible property right, spatial and temporal adaptation strategies. 2) Economic incentives (water market) can facilitate improvement of irrigation techniques, investment in adaptation actions. 3) Public participation should incorporate farmer level planning and management, and provide more information to improve the social learning process.
Our analysis demonstrates that, with regard to water management and climate change, the primary focal point for management policy and institution devising should be on the facilitation of 1) interaction of multilayer institutions, 2) coordination of stakeholders, 3) effectiveness of property right regimes, and 4) learning from the past and other places with low transaction costs.
As a first line of defense on public health and safety, water resource practitioners must consider water quality in long-term climate change planning. While water is a major factor in discussions around extreme events, focus tends to disproportionately be on the linkage with supply and availability rather than quality. Water quality threats from extreme events, such as drought and wildfire, are becoming more commonplace, globally affecting drinking, domestic use, food production, and ecosystem health. As an added layer of complication in California, there are currently no legal requirements for water utilities to plan for or implement strategies for adopting to climate change impacts on water quality. To begin understanding why water quality and extreme events are not prioritized by state policy, this paper examines whether there is a mismatch in the supply of science for meeting managerial science demands. Science supply is defined as the subset of published literature that addresses water quality and extreme events or water quality and climate change in California. Science demand in this paper is defined using water quality and extreme events data from a 2015 survey of California public drinking water systems with more than 200 service connections. The survey collected information on current water quality threats, the severity of these threats, and specific extreme events that trigger or worsen these threats. To evaluate the degree of fit of science supply with sience demand, survey and published literature results are compared using an alignment/misalignment typology based on the proportion of respondents and articles reporting linkages between different water quality threats and climate change. Results show some level of misfit in 23 of 48 surface water quality -- extreme events linkages. Surface water salinity was linked to drought by 77% survey respondents while only 12% of publications mentioning salinity also mentioned drought. Of eight possible extreme events that could be linked with each surface water quality threat, eutrophication produced the largest number of misfit combinations (5). Every groundwater quality threat examined shows some level of misfit between demand and supply for at least one extreme event. The linkage between agricultural contaminants and extreme storms is the largest misfit. Groundwater contamination from agriculture was linked to extreme storms by 24% of respondents, while 80% of articles mentioning agricultural contamination also mentioned extreme storms. The results of this study help identify how water quality and climate change science supply can better meet the science demand of drinking water practitioners by comparing on-the-ground exposure with available literature. This study contributes to the growing body of literature on fit/misfit between science supply and demand. Furthermore, the results of this study demonstrate a method to more accurately inform the integration of climate change science into water quality research and policy priorities through ground-truthing.
Many river basins in the world are impacted by extreme hydrological events (droughts and floods). Such characteristics may be intensified in the future by the climate changes that the planet is experiencing. The objective of the paper is to characterize the climate spatial variability and the mechanisms used to deal with extreme events in the Capibaribe River Basin (CRB) – Brazil. The CRB is located in the Pernambuco State – Northeast Brazil and its drainage area is approximately 7454 km2. The Capibaribe River runs in the direction west-east to the Atlantic ocean. This characteristic defines the high spatial variability of the climate in the basin. The west portion is characterized by shallow soils, Caatinga vegetation (thornscrub, cactus, and bunch grasses), and a semiarid climate with 550 mm yr−1 of rainfall and mean air temperatures between 20 and 22◦C. Periodically, this region suffers with the consequences of drought events. Whereas the east part of the basin is characterized by deeper soils, Atlantic Forest vegetation, and a humid/sub-humid climate, with 2400 mm yr−1 of rainfall and mean air temperature between 25 and 26◦C. During a long time, the cities located in this region were affected by flood events (emphasis for the city of Recife, the capital of Pernambuco state).To identify the level of climate variability in the CRB, a comparison with other regions was accomplished in order to situate the study area in terms of vulnerability caused by this characteristic. Similar comparison has been done with solutions developed around the world with the objective of identifying the level of relationship between technology, the community and extreme events in sites that have to face both shortage and excess of water. For example, it is useful the analysis of historical information related to natural phenomena behavior and the evaluation of the infrastructure adopted in the basin to reduce the vulnerability. The main strategies identified for dealing with drought events in the basin are the construction of large reservoirs for urban supply and several local technologies for rural supply such as rainwater collection, groundwater exploitation and small reservoirs. On the other hand, the only action for flood control in the basin is the use of large reservoirs. This solution has succeeded so far despite the severe flood events occurred in 2010 and 2011 in Pernambuco state. It is expected that the results of the study can contribute to discussion around the following issue: are the strategies of adaptation available in the region capable of facing the impacts caused by the climate change? This is especially important in regions subjected to hydrological extremes as CRB. The Capibaribe River Basin Committee and the Water State Agency are the suitable places to take this discussion forward.
Intergovernmental Panel on Climate Change (IPCC/AR5) mentioned that flood and storm surge will be more serious in lower zones caused by sea level. It is anticipated that intense typhoon will be formed stronger and it will bring flood and storm surge on the same time in Japan because of higher sea temperature. Although many studies have done on impacts on each flood and storm surge, few studies have done on a compound disaster involving these two events. To understand the impact of compound disaster, we try to estimate the damage cost in Japan for the compound disaster.
Flood and storm surge coincide as the compound disaster are selected considering damage in lower areas in Japan. We focus on low atmospheric pressure at typhoon because almost compound disasters selected are derived typhoon. The magnitude of the tide level and daily rainfall which can cause compound disasters are calculated from the relationship between annual minimum atmospheric pressure and tide level deviation, and between annual minimum atmospheric pressure and daily rainfall. The tide level data from 59 tide-gauge stations in Japan over 16 years, the daily rainfall data from 143 rain gauges in Japan over 51 years, and the atmospheric pressure data for each observation station are used for analyses on the tide level and daily rainfall. We distribute spatially the tide level and daily rainfall by means of Inverse Distance Weight (IDW) method. 2D non-uniform flow model expressing the inundation depth is calculated using daily rainfall distribution as input data and the tide level data on coastline in Japan as a boundary condition. Damage cost is estimated using inundation depth calculated by the above method and prices per unit of area calculated by each land use developed by the flood control economy investigation manual. Inundation depth and damage cost are calculated with one square kilometer mesh, with a land use inventory having 11 classifications including rice field, farmland, building site, golf course, main road site, forest, wasteland, other site, river and lakes, beach and sea area is used for the damage cost estimation.
The total damage cost in whole Japan for 50-year return period of compound disaster is 88 trillion JPY. The compound disaster damage costs of Tokyo, Aichi, and Osaka prefecture are higher than any other prefecture and the amount of damage cost in the three prefectures accounts for 33% of the total cost in Japan. Asset values of these prefectures are higher and most of their areas located on low altitude areas compared with the others. The damage cost by the Ise Bay Typhoon in 1959 which actually bought a compound disaster in Japan is compared and shows good agreement with this estimation.
Results show where government should invest intensively in disaster prevention by infrastructure in high-risk area to raise resistance to water disasters in Japan. This can support considering city planning based on the regional characteristics. Our result can contribute to flood control design and the efficient adaptation method against water disasters.