Economic analysis of the long-term effects of groundwater salinity: bringing the farmer’s perspectives into policy

Abstract

This research estimates the economic losses at the farm level caused by groundwater over-exploitation and by seawater intrusion. The problem of coastal groundwater salinity was tackled by considering its hydrological, agronomic and economic aspects. Economic analysis for competitive use vs. regulated management regimes was carried out, considering constant and adaptive watering techniques. We concentrate on the farmers' perspective of water as an input in agriculture, and assess discounted net present value over a period of 30 years. The ultimate goal of this research is to raise the awareness of farmers and policy makers by demonstrating the economic impacts (from the farmer's point of view) of over-exploitation. Our findings for Apulia Region (Southern Italy) indicate that the slowness of the longterm effect of salinity and the ability of farmers to adapt irrigation profiles suggest broadening the perspective of policy intervention. For an effective management of this common resource, policy makers should follow a more comprehensive approach based on economic analysis.

Politiche di gestione della risorsa idrica sotterranea a fini irrigui. Analisi delle preferenze degli agricoltori

“…Meno diffusa è la consapevolezza del peggioramento qualitativo della risorsa irrigua da fonte sotterranea, specificatamente in termini di incremento di salinità. Come hanno fatto notare Giannoccaro et al (2017), sebbene in Puglia sia in atto un processo antropico di salinizzazione della falda, tale processo avviene ad una velocità e con una progressione molto graduali, da rendere impercettibili agli agricoltori le sue conseguenze.…”

“…Questo fenomeno si determina quando gli utenti, perseguendo i propri interessi, ignorano gli effetti delle loro azioni sulla risorsa e su altri utenti. Infatti, nel caso specifico, quando una falda è sfruttata da un ampio numero di soggetti indipendenti, ciascun utilizzatore non è incentivato a conservare la risorsa, poiché non è certo che i risparmi individuali siano di personale ed esclusivo beneficio, potendo essere sfruttati anche da altri utilizzatori 2 (Giannoccaro et al, 2017). Pertanto, si può anche affermare che ogni singolo utente qualora fosse consapevole delle conseguenze della sua azione sul sovra-sfruttamento della risorsa, non sarà disposto a ridurre il suo prelievo senza la certezza che il risparmio ottenuto sia a suo esclusivo vantaggio.…”

Assessing Reclaimed Urban Wastewater for Reuse in Agriculture: Technical and Economic Concerns for Mediterranean Regions

“…In this case, the benefit of groundwater replenishment is also accounted for, keeping invariant additional reclamation costs. The economic benefit of preserving groundwater from salt intrusion in Puglia is reported in [28].…”

“…Finally, PE capacity is used to determine the size at which, according to the treatment features and taking the irrigation water value of 0.21 EUR/m 3 as assessed in [27] or the economic benefit of preserving groundwater from salt intrusion (0.22 EUR/m 3 ) as reported in [28], it is economically feasible to provide WWTPs with tertiary treatment for irrigation purposes (Table 1).…”

The Magnitude and Cost of Groundwater Metering and Control in Agriculture

“…In general, the M&C system is fragmented, and current compliance with the regional law falls far short of the target [22,23]. In many areas where groundwater is the main freshwater source, pumping rates exceed the natural recharge rate and cause continuous water-table drawdown, well depletion, increased pumping costs, and severe seawater intrusion in coastal areas [17,18].…”