There should be some balance among land management BMPs and coastal development and urbanization. Man has limited ability to permanently control rivers, flooding and alter tidal influence. However understanding and applying watershed management, stream, river, estuary and marine systems, potential for sea level rise, severe cyclonic weather and winds, recognizing sensitive ecological habitats will help identify vulnerabilities and sustainable development issues that may be best addressed by a professional interdisciplinary resource team. Failure to recognize the natural systems and our influences upon them is a limitation we often have had to deal with. The US EPA has put out various documents such as mitigation measures associated with the coastal zone management act (about 300-400 pages). You might find this helpful tool for coastal conservation management. To fully understand much of the past land use and urbanization impacts within coastal areas, I would recommend development of LiDAR coverage DEM in GIS for sufficient ground based elevation detail, in most cases showing channel detail, past diversions, ditching and dikes, truer drainage boundaries, etc. See our researchgate 2015 paper and powerpoint for examples of LiDAR detail in a coastal area used to revise and georeference channel networks and hydrologic boundaries. Although past US Corps of Engineers activities included substantial modifications to some coastal systems such as constructing the Atlantic Intercoastal Waterway, channelization of rivers and ports for navigation, they have also developed advisory materials on wetlands and waters regulations and activity limitations and mitigations, some applicable to maintaining the quality and functions of coastal systems.

Both the up and down streams need to be carefully managed through integrated soil, water, vegetation and human resource management following appropriate land use system as per capability class. Similarly, anthropogenic behavior also need to be sensitized at both the levels.

Thank you Dr William, your answer is very inspirational. I will look for the indicated references and read them carefully.

Dear Adil,

you are right to ask this question on intervention in the natural order related to river basins. True that upstream erosion rates are higher generally than in previous generations. usually the erosion has increased due to deforestation in montane environments or to over-grazing pressures. Some suggested solutions I fear could exacerbate the situation on the one hand or reduce the natural erosion to such an extent that flood plains downstream fail to receive their normal supplement of silts and clays which help fertilise the fields.

As a general rule it is to work with the river rather than against it. The building of levees and canalising channels has proved disastrous in many floodplain scenarios. Better to allow the river to adjust its channel and farm floodplain areas in a way that is compatible to good husbandry. Building developments should NOT be permitted on floodplains ; it usually ends up with pressure on local/national governments to implement flood defence work that exacerbated the situation.

Similarly, attempts to dam waters in upland areas can lead to the need, in times of prolonged rainfall, to open dams when the river is already at near flood level. Dams also extract sediment from the system.

Any remedial work on river systems has to be carried with great care and a clear knowledge of any deleterious effects that could ensue.

kind regards

George Strachan

Thank you Dr. George for your truly inspiring answer. I totally agree with you. We (scientists) are trying to guide decision-making toward harmonious territorial management where socio-economic development fits into its natural context by ensuring the sustainability of resources (at the catchment scale) and by providing conditions of adapted and "logical" well being. However, the administrative complications (national, regional and local divisions that differ from natural limits), the currently very demanding consumer lifestyle ... make that, almost always, the decisions miss our recommendations.

Regards