13.-0116. Automatic surge flow and gravitational tank irrigation system.

Watsan matters
13.-0115. Automated irrigation.
13.-0114. Attenuation.
13.-0113. Atmosphere.
13.-0112. Assisted sedimentation.
13.-0111. Assisted sedimentation with filtration.
13.-0110. Ash from sludge.
13.-0109. Artificial recharge.
13.-0108. Artificial groundwater recharge..
13.-0107. Artificial fertiliser.
13.-0106. Arthropod.
13.-0105. Artesian.
13.-0104. Artesian water.
13.-0103. Artesian spring.
13.-0102. Arsenite.
13.-0101. Arsenic removal technologies.
13.-0100. Arsenic removal filter.
13.-0099. Arsenate.
13.-0098. Arid.
13.-0097. Arid region.
13.-0096. Arbovirus.
13.-0095. Arborloo.
13.-0094. Aquitard.
13.-0093. Aquifer..
13.-0092. Aquifer pollution vulnerability.
13.-0091. Aquifer ( unconfined ).
13.-0090. Aquifer ( confined ).
13.-0089. Aquiclude.
13.-0088. Aqueduct.
13.-0087. Aquatic.