engleski

Managing water commons using mediator variables to bridge the gap between environmental factors and anthropogenic pollution indicators

Water is the lifeblood of all life, so population concentrates near potable sweet water sources. People also concentrate near the coastline for economic reasons. Much of the drinking groundwater resources in the Croatian coastal area is stored in karst aquifers. Because of its quick pass- through nature and nonpoint source pollution, its protection is challenging. There have been many monitoring and measurement challenges in the past. For example, there was no empirical confirmation of a conjectured link between rainfalls and microbiologic pollution in the monitored coastal areas. Before the use of δ2H and δ18O stable isotopes as mediators for the analysis of groundwater dynamics in karst aquifer characterisation, the causal links between rainfall and aquifer- as well as marine pollution were elusive. Data analysis of groundwater dynamics required also some dynamic statistical modelling, as for example dynamic panel data modelling in form of a General Method of Moments with First Differences transformation to control for unobserved time- invariant individual effect heterogeneity in. Static statistical models that include δ18O values successfully represent the microbial pollution variations within a closed system. We understand this to be a characteristic of a stock pollution. At an open sea location, the results of static microbial pollution modelling have not been as good. Dynamic modelling using first differences of δ18O values indicate that in these circumstances we deal with flow pollution. Whether a pollutant is a stock or a flow is not only dependent on the pollutant itself, but mostly on the medium, and the environment it is propagating through, as the medium determines its pass-through velocity. Policies regarded as optimal for stock and flow pollutants are different. In terms of Elinor Ostrom categorisation, aquifers are common goods as they are predominantly stocks of water and karst aquifers are common pool resources as they are predominantly flows of water. The question of stock or flow is of great importance to decide whether the regulatory body should use price or quantitative allocation mechanisms. There are circumstances where we would prefer the one to the other because of political and administrative reasons, but it is ultimately up to the marginal costs and benefits to use the one or the other. When supply and demand curves are flat, it is better to use quota-like quantitative methods for avoiding planning mistakes. For inelastic costs and benefits, a price system of regulation is optimal instead. Whether an ecological system produces elastic or inelastic costs and benefits depends on factors such as pass-through velocity and its sustainability. Stocks are common goods and prefer price mechanisms. Flows are common pool resources, and prefer quantitative mechanisms. The amount of pollution which makes a spring unfit for drinking could be at a point where the marginal benefits of an extra unit of output of a pollutant change very rapidly. It is not optimal to regulate prices or impose taxes in such situations. In some situations, mixed schemes may be optimal.

economic institutions ; water commons management ; mediator variable ; pollution measurement ; stock pollutants ; flow pollutants

nije evidentirano