A case study for irrigation modernisation: II

Abstract

Surface irrigation simulation models have seldom been used in engineering practise, and district modernisation is not an exception. Surface irrigation evaluations were performed in the Almudévar irrigation district to obtain the parameters required for surface irrigation modelling. The total district irrigated area was divided into 92 design units, for which a characteristic blocked-end border was defined. Simulation was used to establish the current irrigation performance in each design unit, and district performance contour maps were built. Irrigation performance was characterised using potential application efficiency, with an average of 54%, and irrigation time, averaging 6 hr ha -1 . Simulated potential application efficiency of the low quarter was similar to the Seasonal Irrigation Performance Index (an estimate of irrigation efficiency) presented in the companion paper. A set of seven modernisation scenarios was defined. Two

Analysis of an irrigation district in northeastern Spain

“…Similar 537 findings (but different rates) were reported in previous works on surface-irrigated 538 districts (Clemmens and Dedrick, 1992; Faci et al, 2000). 539…”

“…Irrigation requirements were estimated using the standard FAO procedures, as 217 described by Doorenbos and Pruitt (1977) The performance measure used to characterise water use in the LQD was the 239 Seasonal Irrigation Performance Index (SIPI), as defined by Faci et al (2000) and applied 240 to the AID. The SIPI is defined as the percentage of net irrigation requirements (NIR) to 241 seasonal water use, estimated from billing records (WU, mm).…”

“…for districts using open ditches for water delivery, such as the AID (Faci et al, 2000). The 181 general analysis examined the seasonal volume of water billed during the three years of 182 study for entire district area.…”

Limitations to adopting regulated deficit irrigation in stone fruit orchards: a case study

“…Volumetric stoniness (S, %) was determined for each sample from the weigh of fractions above and below 2 mm, soil bulk density (ρ b , Mg m -3 ) and the stone density. Soil bulk density and stone density were estimated as 1.40 and 2.65 Mg m -3 , respectively, in agreement with previous works in the area (Playán et al, 2000). Gravimetric f ield capacity (FC, %) and wilting point (WP, %) were estimated at the laboratory using pressure plates (Hanks, 1992).…”

“…Due to the sampling density and the large spatial variability of RAW, it was not possible to map this variable with more detail. The magnitude of RAW spatial variability was similar to that reported in other areas of the central Ebro River basin (Playán et al, 2000;Lecina et al, 2005). The lowest observed values of RAW are compatible with the usual local irrigation requirements and practices (daily replacement of the crop water requirements), avoiding important deep percolation losses.…”