Protected springs water resilience in watershed of south of Brazil

Todeschini, Raul; Swarowsky, Alexandre; Panziera, André Gonçalves; Erthal, Guilherme Lemes; Horn, João Francisco Carlexo; Cruz, Jussara Cabral

doi:10.1590/2318-0331.272220220019

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Scientific/Technical Article • RBRH 27 • 2022 • https://doi.org/10.1590/2318-0331.272220220019 copy

Protected springs water resilience in watershed of south of Brazil

Resiliência hídrica de nascentes protegidas em bacias hidrográficas do sul do Brasil

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Springs of the Vacacaí-Mirim river basin, in the Atlantic Forest biome, are protected by law because they provide an environmental service through water supply. No study provided identification, estimates and information about the seasonality of water resilience and environmental conditions of these springs, which supply the central region of the state of Rio Grande do Sul, Brazil. This study monitored headwater flow volume and interpreted the results through seasonality and use of the flow duration curve, characterizing the springs and showing the water production capacity. As a result, the springs presented higher flow duration curve contrasts. Considering consistent monitoring time, differences in flow characteristics occurred in the analyzed springs allowed to qualify based on their persistence, temporary or ephemeral flow, showing which springs are more resilient. The shape of the flow permanence curve was different for each spring in the basin. The study was able to determine the flow duration curve and confirm the resilience and reality of a headwater of the Vacacaí-Mirim river basin, being more accurate and necessary than estimates of flow from springs.

Keywords:
Base flow; Water supply; Hydrology

Class		Agricultural lands	Building area	Eucalyptus forest	Grass lands	Native forest	Water resource	Access roads	Total Catchment Area
N1	ha	<0.01	<0.01	1.12	0.17	0.72	<0.01	0.14	2.15
N1	%	0	0	52	8	34	0	6	100
N2	ha	<0.01	<0.01	1.87	<0.01	0.02	<0.01	0.06	1.95
N2	%	0	0	96	0	1	0	3	100
N3	ha	2.38	<0.01	0.43	0.37	3.21	0.27	0.08	6.75
N3	%	35	0	6	6	48	4	1	100
N4	ha	<0.01	<0.01	3.54	<0.01	0.54	<0.01	<0.01	4.08
N4	%	0	0	87	0	13	0	0	100
N5	ha	<0.01	<0.01	12.21	0.22	0.80	<0.01	0.30	13.52
N5	%	0	0	90	2	6	0	2	100
N6	ha	0.81	0.04	1.26	0.25	1.03	<0.01	0.13	3.53
N6	%	23	1	36	7	29	0	4	100
CO	ha	179.9	7.4	210.9	98.75	216.3	10.9	16.2	732.4
CO	%	24	1	28	13	30	2	2	100

Spring	Latitude/Longitude	Altitude (m)	Slope (m/m)	Form Factor	Mean flow (L s^-1)	Description of Use and Cover Soil
N1	53°46'34”O 29°36'08”S	429	0.15	0.20	0.37	Surrounded spring in the middle of native forest, with on-site maintenance of tree; downstream from grasses, a small dirt road, and eucalyptus forest. Contains no agricultural components.
N2	53°46'36”O 29°36'14”S	427	0.09	0.55	0.34	Surrounded spring in the middle of native and eucalyptus forest. Contains no agricultural components.
N3	53°46'42”O 29°36'44”S	457	0.07	0.43	0.25	Spring considered degraded due to loss of original forest cover and no forest restoration treatment. Located in the middle of eucalyptus forest, accessible to animals, especially cattle. Downstream from has native forest, agricultural area, grasses, a dirt road, and a small reservoir.
N4	53°47'01”O 29°36'27”S	447	0.08	0.60	0.48	Enclosed spring in the middle of native forest, with a high density of araucaria trees. Management is of regeneration by isolation. Located downstream from eucalyptus forest and fragments of native forest
N5	53°47'34”O 29°35'49”S	429	0.08	0.8	3.75	Spring that has its native characteristics preserved, i.e. no forest restoration treatments. Established in the middle of eucalyptus and native forest, freely accessible to animals, mainly cattle. Downstream from eucalyptus cultivation as well as small roads and grassy areas. Contains no agricultural components.
N5	53°47'34”O 29°35'49”S	429	0.08	0.8	3.75	It should be noted that the collection point is located approximately 100 m downstream of the actual spring, due to the irregular topography and difficulty in installing instruments.
N6	53°47'14”O 29°36'13”S	428	0.13	1.30	0.37	Spring surrounded by dense vegetation in an advanced successional stage, with an 8-year regeneration treatment. Downstream from residences, grasses, agricultural areas, a dirt road, and eucalyptus and fragments of native forest.
CO	53°46'21”O 29°36'35”S	410	0.08	0.62	136.16	Outlet of the basin under study, collecting water from the above springs as well as from other water courses.

WATERSHED	PERSISTENCE	RESPONSIVENESS
N1	Temporary	Intermediate
N2	Ephemeral	Intermediate
N3	Ephemeral	Spiking
N4	Ephemeral	Intermediate
N5	Perennial	Lagging
N6	Perennial	Spiking

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E-mail: rbrh@abrh.org.br

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[1] E-mails: todeschini.raul@gmail.com (RT), aleswar@gmail.com (AS), andregpanziera@gmail.com (AGP), gerthal09@gmail.com (GLE), jfchorn@gmail.com (JFCH), jussaracruz@gmail.com (JCC)