(2007) cite Pakistan Irrigation Department data indicating that 7.2 Gt of sediment was delivered to the Indus Delta at a mean rate of 100.6 Mt/y. Therefore if the delivery of 100 Mt/y of river sediment results in a net land loss equivalent of 47 Mt/y, then the pre-Anthropocene flux estimate of 250 Mt/y (Milliman check details et al., 1984) would result in an active Indus Delta able to both aggrade and prograde seaward. The sediment budget remains qualitative, as it does not take into account subsidence across the delta, for lack of quantitative data. Satellite analysis suggests that there is significant sedimentation

within the inner tidal flats of the Rann of Kachchh (Fig. 10), further complicating a full quantitative assessment. Although part of the Rann of Kachchh (Lake Sindri south of the Allah Bund) underwent >1 m of incremental tectonic subsidence in 1819 it is not known

whether slow secular subsidence occurs between earthquakes, either due to tectonic subsidence or sediment compaction. The 1945 Makran earthquake resulted in a tsunami that inundated the ports of Karachi and Mumbai, but no record of its effects have been preserved in the delta region (Bilham et al., 2007). The recent 2001 Mw = 7.6 Bhuj earthquake (Fig. 3) resulted in local subsidence in the southeastern Rann of Kachchh and was responsible for an estimated 20,000 deaths (Bodin and Horton, 2004). Tidal energy has been focused toward the eastern margins of the delta, apparently responding to changed hydraulic gradients or to the absence PLX-4720 manufacturer of sediments from the now inactive eastern distributaries. Evidently the sediment supply to Lake Sindri in the past 200 years has been insufficient to fill the tectonically induced basin since it remains a 20 km × 30 km basin, 1–2 m deep (Fig. 10). In contrast, the tidal flats in the western part of the Indus Delta appear

to be more stable, possibly protected from tidal and wave reworking of the shoreline by the absence of tectonic subsidence or possibly due to the presence of slow uplift. The effects of the transition to the Anthropocene delta due to its much-increased Adenylyl cyclase abstraction of water upstream are pronounced and well documented: seawater intrusion, soil salinization, deforestation of mangroves, reduced supply of surface- and ground-derived drinking water, low irrigation flows, and greatly depleted fisheries. Shrimp production has decreased by 90% (Inam et al., 2007). The delta’s mangrove forest, which covered ∼2500 km2, has been reduced by 60% (Kamal, 2004). The degraded mangrove ecosystem is virtually mono-specific, comparatively stunted, with losses of about 2% per year (Asianics Agro-Dev 2000). The increase in salinity during periods of low flow, and from the effects of upstream irrigation, has reduced the suitability of the delta for the cultivation of red rice, and for raising livestock.