Estimativa de recarga em áreas urbanizadas: estudo de caso na bacia do Alto Tietê (SP)
Bibliographic record
Abstract
The Upper Tiete Watershed (UTW) has a population of 19.5 million in an area of 5,985 km 2 , which corresponds approximately to the contour of the Metropolitan Region of Sao Paulo (MRSP), Brazil.The UTW is comprised of two major aquifer systems: the Sedimentary Aquifer System (SAS) (1,452 km 2 ) and the Crystalline Aquifer System (CAS) (4,238 km 2 ).The importance of groundwater in the MRSP has increased substantially during the last 20 years.Several industries and condominiums are using groundwater as a complementary and often exclusive source of water supply, extracting a volume that corresponds to approximately 13% of the total volume of water distributed by the public supply companies.Despite their importance, not much is known about the quality and quantity of the water that recharge these aquifer systems.Besides, in urban areas, the anthropogenic influence causes changes to the natural water recharge patterns of the aquifer systems.This study had the following objectives: i) estimating the recharge of the SAS in two areas with different land use patterns (high and low density of paved surfaces), using different methods (water table fluctuation, Darcyan approach, hydrochemistry, environmental isotopes); and ii) determining the origin of the recharge water (leakage of supply water and sewerage system or natural infiltration of rainfall).The rainiest and driest months for both areas were January and August, respectively, and the total precipitation for the densely paved area was 1,193 mm and 1,407 mm for the least-paved area.The water table fluctuation methodology estimated that natural recharge for the poorly urbanized area is 246 mm/a and 183 mm/a for the densely urbanized area.A value of 481 mm/a was obtained through the Darcyan approach for the more urbanized area and 311 mm/a for the less urbanized area and, if the estimations are accurate, the difference between the results of the different methods indicates the sum of the anthropogenic recharge sources (respectively 298 mm/a and 65 mm/a).Analysis of chemical data for Na + , Cl -, NO 3 -, NH 4 + and SO 4 2-showed the presence of extensive sewerage leakage in both areas.Results from isotopes in NO 3 -for the urbanized area (enrichment of δ 15 N and δ 18 O) and chemical data (DOC, HCO 3 -) indicated that denitrification plays an important role in attenuating the nitrate in the aquifer.The data from water levels, the unsaturated zone and environmental isotopes indicate that rainfall volumes lower than 20 mm/day or 100 mm/month are not able to recharge the aquifer.Data from δ 18 O and δ 2 H collected in both areas lie on a mixing line between the fingerprints of precipitation water (higher than 100 mm/month) and water from the public supply system, indicating the contribution of these distinct sources to the recharge of the aquifers (urban contribution of 14% for the recharge of the less urbanized area and 67% in the more urbanized area, corroborating the results of other methods).The data obtained in this study indicates that leakage of the sewage and water distribution system plays a major role in the recharge of the aquifer and groundwater quality.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".