How does water harvesting (at landscape level) impact micro-climate?

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I hope to gather more evidence and suggestion on the links between intense water harvesting/water shed activities on microclimate - because as a landscape becomes more moist temperature peaks are affected, nitrogen fixation by soil biota accelerated, soil temperature changed with different measures having different impacts. This raises questions on how microclimate can address changes in the macroclimate

see also:

http://www.thewaterchannel.tv/thewaterblog/349-it-is-the-microclimate-you-didn-t-see

keen to get more material on this topic

 

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4 Answers

  1. Very interesting question in deed. I unfortunately have no answer but in my opinion realizing that rainwater is the main driver of groundwater recharge in most areas it is foreseable that rainwater harvesting would portend significant impact of groundwater recharge. Now, the scale of that impact can be quie varied due to several factors but assuming a very efficient and substantial catchment area for the RWH, especially in hilly terrain it can drastically limit groundwater recharge. Just a thought.

  2. Hi, I have been working on hydrological circle and water transfer through it, and impact on climate, question you raised is quite important as it is proven that more water in atmosphere triggers more intense weather, as part of my research is defining thresholds for drought and your issue is exact cause of local or microclimate change. If you use simple thermodynamics equations you will see that energy transfer in small boxes (microclimate level) are highly influenced by amount of free water available, or available water for evapotranspiration, if you extract in any other way water from the system you are influencing drought and supporting system to develop drought prone environment, as each box has its balance equation according to landscape and amount of water in it, structure of urban bounds and etc. As well what is important for microclimate is type of watershed you have, is it steady water surface as lake or rapid one, or is it a swamp each requires different amount of energy to transfer water from surface to atmosphere. So direct answer on your question is that water harvesting is pushing system to more arid in case you are not returning water to the system if you want proof just use simple balance equation and thermodynamics

  3. Shucks, I thought this was a study showing the effect of rainwater harvesting on landsc aping. Meaning does the landscape water supply get cheated if the water off the roof is not allowed to do directly on the landscape instead of into the rainwater storage tank. I have been told that rainwater harvesting will cheat the groundwater and rivers and lakes. I do not think so, but na sayers need proof. Got any?

    1 Comment

    1. What you are saying is that if we save rainwater in storage it will influence process in other water system, simple answer is yes. As all systems are influenced by atmosphere weather so in other words if you store water and make it more available and easier to evaporate than from other resources than you will preserve water in other storages under same weather conditions, that means each weather conditions provide you just some amount of possibility to evaporate the water from your system, so if there is no other artificial extraction from the system just simple natural inflow and out flow storing rainfall water would change processes, never the less if you do not let right amount of rainwater to feed the system than you can create deficit in system as well.

  4. Pls. check the website of GRIWAC, China for further. They, with RWH, changed the micro- climate of whole Gansu province in just 5 yrs. time. The rainfall rose to 500mm annually from 300mm in in just 5 yrs. Rajan Pandey, Nepal