Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Water movement / Drainage, groundwater recharge and runoff (about 65 percent of rain returns to air, 35 percent runs off)
Drainage, groundwater recharge and runoff (about 65 percent of rain returns to air, 35 percent runs off)
Where land precipitation that is not evapotranspired goes: surface runoff, interflow, and deep drainage that recharges aquifers and later returns as baseflow. Also covers capillary rise and solute export.
Boundary: where this process starts
Starts with: Fate of land precipitation
Boundary: where it ends
Ends after: Baseflow sustains streams between storms (about half of streamflow); Surface and quick subsurface runoff reach streams within hours to days
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
- Participant
- Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
- Resource
- Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
- Step
- One thing that happens in a process. Every step has at least one participant and carries evidence.
- Decision fork
- A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
- Loop
- A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
- Size of impact
- Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
- Evidence
- The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
- Boundary
- Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
- Subprocess
- A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
- Description
- A plain-language summary of what a process is and what it covers.
- Hypothesis
- A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.
Every step, with its evidence
The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.
⑂ Fate of land precipitation
Evidence (1) · added by Quanta
- Oki 2006, Global Hydrological Cycles and World Water Resources, Science, doi:10.1126/science.1128845: Global land precipitation about 113,000 km3/yr; ET about 65 percent, runoff about 35 percent (Oki and Kanae). (confidence 0.55)
Evapotranspiration returns water to the air
Evidence (1) · added by Quanta
- Oki 2006, Global Hydrological Cycles and World Water Resources, Science, doi:10.1126/science.1128845: ET about 65 percent of land precipitation. (confidence 0.6)
Surface and quick subsurface runoff reach streams within hours to days
Evidence (1) · added by Quanta
- Beck 2013, Global patterns in base flow index and recession based on streamflow observations, Water Resources Research, doi:10.1002/2013wr013918: Quickflow is the non-baseflow share of streamflow; global mean base flow index is roughly 0.4-0.6, so quickflow is the other 40-60 percent. (confidence 0.45)
Deep drainage below the root zone recharges aquifers (about 10-15 percent of rain, concentrated in the wet season)
Evidence (1) · added by Quanta
- Jasechko 2014, The pronounced seasonality of global groundwater recharge, Water Resources Research, doi:10.1002/2014wr015809: Groundwater recharge is strongly seasonal, concentrated in a few wet months; recharge ratios differ by climate. (confidence 0.55)
Baseflow sustains streams between storms (about half of streamflow)
Evidence (1) · added by Quanta
- Beck 2013, Global patterns in base flow index and recession based on streamflow observations, Water Resources Research, doi:10.1002/2013wr013918: Global maps of base flow index from streamflow observations; mean near 0.5. (confidence 0.55)
Capillary rise returns shallow groundwater to the root zone
Evidence (1) · added by Quanta
- Cuthbert 2019, Global patterns and dynamics of climate-groundwater interactions, Nature Climate Change, doi:10.1038/s41558-018-0386-4: Climate-groundwater interactions: shallow water tables couple to rooting zone and evapotranspiration with hydraulic memory. (confidence 0.5)
Percolating water flushes dissolved ions (calcium, magnesium, nitrate, bicarbonate) out of the profile
Evidence (1) · added by Quanta
- Gaillardet 1999, Global silicate weathering and CO2 consumption rates deduced from the chemistry of large rivers, Chemical Geology, doi:10.1016/s0009-2541(99)00031-5: Large rivers export weathering products as dissolved ions and bicarbonate, scaling with runoff. (confidence 0.55)
Thawing permafrost deepens flow paths and raises baseflow
Evidence (1) · added by Quanta
- Walvoord 2016, Hydrologic impacts of thawing permafrost - a review, Vadose Zone Journal, doi:10.2136/vzj2016.01.0010: Permafrost thaw increases subsurface flow connectivity and baseflow in many catchments. (confidence 0.6)
Groundwater pumping lowers water tables and cuts baseflow
Evidence (1) · added by Quanta
- Wada 2010, Global depletion of groundwater resources, Geophysical Research Letters, doi:10.1029/2010gl044571: Global groundwater depletion estimated at hundreds of km3/yr, exceeding natural recharge in major aquifers. (confidence 0.5)