A Proposed Improvement of Belanti II Tidal Irrigation Scheme, Kalimantan, to Support Leaching of Acid Sulphate Soil Reclamation

The reclamation process of acid sulphate soil of the Belanti II tidal irrigation scheme remains unfinished. During ebb tide, the upstream acidic drainage water retains and settles in the irrigation canals. During high tide, the acidic water flows back into some parts of the agricultural land and reduces rice productivity. The measured pH is about 2.5 ~ 3.5 and the measured electric conductivity is about 0,25 ~ 0,35 mS/cm. Sedimentation in the middle to the end of the primary, secondary, and collector canals and tidal pond at the upstream end of the primary canal, preventing the leaching process of sulfuric acid soil. Primary canal normalization as an alternative solution to increase the capability of acidity leaching is proposed. Leaching the acidic soil of Belanti II irrigated area of 3.976 ha requires 500 m3/ha/day of freshwater, equivalent to 1.998.000 m3/day. The one-dimensional HEC RAS mathematical model is used to evaluate the hydraulics performance to support the leaching process. The hydraulic analysis was carried out using two tidal cycles on the existing channel and the normalized channel. Channel normalization has succeeded in reducing the water supply deficit to support the leaching process from 39% to 9%.

Representing ancient southern Mesopotamia irrigated landscapes in an agent-based model

<p>In order to explore possibilities of mimicking the operation of an irrigation system under varied scenarios, the authors have designed the Irrigation-Related Agent-Based Model (IRABM), providing a platform for integrating human and non-human agents (water managers, farmers, barley, river, canals, and gates) together and analyzing the interactions among these agents. IRABM illustrates how barley yields respond to varied irrigation strategies and how patterns of yields vary among the levels of individual farmers, canals, and the whole irrigation system. The model proves how this type of theoretically and empirically informed computer model can be used to develop new insights into studying and simulating interactions between individuals and their environment in an irrigation system. Furthermore, it demonstrates how and why irrigation and yield patterns can emerge from changing actions.</p><p>One of the applications of the model will be for ancient Southern Mesopotamia, the pluvial land between the two rivers Euphrates and Tigris. Our knowledge of irrigation management and irrigated-landscapes in southern Mesopotamia fairly scant due to lack of data, but also because attention for the details of irrigation management has been ignored in archaeological analysis to date. IRABM offers options to synchronize the general features of irrigation systems to the specifics of Mesopotamia. How to represent ancient Mesopotamia in IRABM is the key question we address in this paper.</p><p>Given the low precipitation, the available water in Mesopotamia’s watercourses for cultivation was vital. This prompted the establishment of irrigated agriculture, leading to its sophisticated irrigation systems over time. Management of irrigation activities is both related to water volumes in the different (levels of) water courses, and to the size of a system. Because of the expanding Mesopotamian society, and this its irrigated areas, the unpredictable water availability, and the threat of water scarcity during the crop growing period, coordinating issues were critical.</p><p>How to present ancient Mesopotamian irrigation systems in IRABM and how to fully explore the temporal and spatial coordination issues is our current challenge. Using the standard composition of irrigation systems in the primary canal, secondary canals, and tertiary canals, we can draft sizes of these levels. The cultivated size of agricultural land varied among the different levels of canals. Generally, the primary canal would supply 5 to 6 villages, while the second and tertiary canals might irrigate land in 2 to 3 villages and 1 village, respectively. The main crops were winter crops (barley and wheat). The water regimes of the two rivers are characterized by great, rather unpredictable fluctuations that do not coincide with winter crops.</p><p>This presentation will discuss how the data on ancient Mesopotamian irrigation (including water availability in rivers, canals, and fields, and surface areas of irrigated landscapes) can be meaningfully included in an ABM that allows studying how small/short processes contribute to large-scale patterns and processes occurring in irrigation systems.</p>

Epithelial dynamics shed light on the mechanisms underlying ear canal defects

ABSTRACTDefects in ear canal development can cause severe hearing loss as sound waves fail to reach the middle ear. Here, we reveal new mechanisms that control human canal development and highlight for the first time the complex system of canal closure and reopening. These processes can be perturbed in mutant mice and in explant culture, mimicking the defects associated with canal atresia. The more superficial part of the canal forms from an open primary canal that closes and then reopens. In contrast, the deeper part of the canal forms from an extending solid meatal plate that opens later. Closure and fusion of the primary canal was linked to loss of periderm, with failure in periderm formation in Grhl3 mutant mice associated with premature closure of the canal. Conversely, inhibition of cell death in the periderm resulted in an arrest of closure. Once closed, re-opening of the canal occurred in a wave, triggered by terminal differentiation of the epithelium. Understanding these complex processes involved in canal development sheds light on the underlying causes of canal atresia.