comprehensive vs. accurate

development of What? I'am just guessing what are you talking about. You have to be more specific in your statements

Vesi :)

I agree with the statement.  WMPs designed to reduce peak flows may neglect the spatial and temporal distribution of water availability to the ecosystems in question.  The flow routing may also change the temperature and chemistry of the water.

Hi Hamzeh,

I just saw a documentary on the link between the health of the Great Barrier Reef corals and the cutting of tropical forest for agriculture in the Northeast of Australia. As Wes has pointed out flow routing can change temperature and chemistry of run-off as well. In the case of of Australia's Northeastern territories, it impacts on the runoff to the Great Barrier Reef. And in that case it is not that much peak flow which is important, but typically Wes' nutrient loads.

The development in the tropical mainland in Australia caused the dying off of part of the corals of the Great Barrier Reef. The main cause for this is that originally almost clear water (that area of Austrlia receives more than 10 meters! of precipitation per year) due to deforestation led to an increase in erosion of the original forest soils (turned into agricultural land). This caused an increase in silt content and sedimentation in the Great Barrier Reef waters as well as strongly increased levels of nutrients from the agricultural areas. Increased settling also induces the same increase in sediment  content and increased levels of nutrients. As a result algae bloomed in the areas of the Great Barrier Reef where the silt and nutrient substances increased due to runoff from areas in the watershed where tropical forest is and has been cut.

Algal bloom caused the death of the corals in the reefs impacted by increased nutrient levels from the mainland areas which had been 'developed'. The algae when strongly growng on the reefs, increase the attenuation of incoming sunlight towards the corals, the effects of this on corals are very well known,... a sudden death so to say.

Knowing that the Great Barrier Reef is also a defense line against floods and storm surges of the Pacific Ocean, the coastal areas face increased flooding risks. Or,... how all these natural systems are coupled in a fragile equilibrium, which can be strongly shifted towards degradation of the Great Barrier Reef corals due to human settlement, forest cutting, agricultural practices and indeed Water Management practices on the tropical mainland. I am sorry to say that humankind is not yet capable of organising its settlements in the way nature has developed the equilibria between its different ecosystems for millions of years.

I don't want put the blame on the Australians here, because all continents on Earth have and are doing exactly the same as the Australians. The difference is that in the Northeast of Australia, settlement is pretty recent, while typically in Africa, Europe and Asia, it is much less recent, with deleterious consequences for many watersheds and the seashores where continental run-off comes to an end.

Have a nice day,

Frank

I don't agree with this statement. Here, you're talking about translating changes in peak flows into ecological impacts...but what do those changes tell you about the ecological health of the watershed ? => Nothing but an index of watershed flow changes over several time periods, to be used as a base for further explorations of changes (more roads, deforestation rates increases...), if any significant. I assume that you're just comparing flows given by a gauging station.

Then you can think of potential ecological impacts and try to collect some evidences. Changes in the water regime means a lot of cumulative effects: temperature, chemistry, morphology of the river banks so changes in habitat availibility...and so on.

Actually, you might want to use peak flow measurements as a factor of ecological impacts among others that describe watershed conditions, not as THE proof of ecological impacts.

Peak flow will be changed if any alteration is done within the watershed. If the watershed is developed, conserved, peakflow might reduce while construction activities, clearing, agricultural activities etc. will increase the peak flow.