UMUHIMU WA MISITU KWENYE VYANZO VYA MAJI

Bila kutunza misitu hatuwezi kupata maji.

Maji-Ralilimali iliyo chanzo cha maisha. Misitu ni chanzo chake.

Maji ni moja kati ya rasilimali muhimu sana ambayo chanzo chake ni misitu. Ni kitu muhimu kwa viumbe hai vyote katika kujihakikishia maisha. Umakini katika uratibu wa misitu ni muhimu sana ili kuhakikisha maji ya kutosha yanapatikana kwa kizazi kilichopo na kijacho. Kila mkusanyiko fulani wa maji yaliyohifadhiwa au kujikusanya kiasili (water reservoir) yanakuwa na chanzo fulani yaalikotoka na hapo yaamekuja kwa kufuata mkondo (hata kama ya mvua)

Kwani Maji Yanatoka Wapi?

Mvukizo kutoka makusanyiko makubwa ya maji mfano bahari hubeba unyevu unyevu ambao hutengeneza mawingu angani. Upepo kutoka baharini huweza kuyasukuma hayo mawingu  juu zaidi. Kutokana na kuongezeka kwa ukubwa wa mawingu na tofauti  za kimgandamizo mawingu huanza kudondoka kama mvua. Mara nyingi mvua huwa kubwa maeneo yenye misitu mikubwa kwasababu miti husaidia kuzuia upepo unaovuma kuyapeleka mawingu maeneo mengine.

Maeneo yote hasa yenye misitu ambako mvua zikinyesha maji huanza kufuata mikondo midogo midogo (runoffs) au kupitia mikondo ya ndani kutokana na uelekeo wa mwinuko (underground streams) kwenda maeneno ya kujikusanya (mto au mabwawa) huitwa catchment areas.

Jamii  yenye shida ya maji huishi kama watumwa.

Je Misitu na Matumizi Yake Hupunguza Upatikanaji wa Maji?

Misitu hutoa tathmini (determine) ya kiwango (quantity), kima (rate) na ubora (quality) wa maji yanayopita katika mikondo mbalimbali na baadaye kuhifadhiwa maeneo mbalimbali kama mabwawa. Pamoja na misitu kuwa chanzo cha maji, lakini huwa chanzo na makao ya rasilimali nyingine kama wanyamapori, kutunza uasili wa eneo (nature conservation), uvunaji wa mbao, uchimbaji wa madini, tafiti za kitaaluma, ufugaji nyuki, soko la mauapori, utalii na kujifurahisha.

Shughuli hizo zote wakati fulani huhusisha magari kuingia msituni hivyo kuchafua mazingira, kuongeza mmomonyoko wa udongo, kuharibu uoto na uchomaji moto. Wakati mwigine udongo unaoshika katika magurudumu ya magari huweza kuhamisha au kusafirisha fangasi wanaosababisha magonjwa kwa miti kutoka sehemu moja kwenda nyingine hivyo kuongeza uharibifu zaidi. Kuzuia uharibifu huu usitokee inatakiwa kuwe na mpango wa pamoja wa kuratibu na kuaendesha maeneo ya vyanzo vya maji (Integrated Catchment Management), mpango shirikishi na angalizi wa uratibu wa maji, aridhi, uoto na rasilimali nyingine.

Ukataji miti au uchomaji moto ovyo hupelekea uondoaji wa kudumu wa miti hasa yenye mizizi mirefu ambayo hutumia maji yaliyo chini ya aridhi. Kadiri mvua inavyonyesha maji mengi yatakuwa yanaingia chini ya aridhi bila kutumika hivyo kiwango cha maji chini ya aridhi kinaongezeka (ground water level rises) na kuyeyusha chumvichumvi ya aridhini. Maji ya aridhini ambayo sasa yatakuwa yenye chumvi, yanaweza kupanda hadi juu ya aridhi na kutengeneza maeneo ya aridhi yenye chumvi ( salt scalds) au kwenda hadi kwenye mabwawa na kuyafanya yawe na maji chumvi. Maji yakiwa na chumvi ni moja kati ya uchafuzi wa maji (Salinity is one of water pollution), hivyo kwa lugha rahisi, ukataji wa miti maeneo ya misitu inakonyesha mvua na maji kuelekea katika mabwawa (catchment areas) husababisha chumvi katika mabwawa husika. Umakini katika uratibu wa misitu, utapunguza tatizo hili.

Ukataji ya asili miti kwaajili ya kuchoma mkaa ni chanzo kikubwa cha uharibifu wa misitu

Mmomonyoko wa Udongo

Mmomonyoko hutokea pale ambao udongo unaondolewa kwenye aridhi yake ya asili kwa maji au upepo. Hii hutokea wakati miti na uoto ulio juu ya aridhi umeondolewa. Aina ya mmomonyoko iitwayo splash erosion hutokea wakati matone ya mvua yanapopiga aridhi tupu na kumomonyoa aridhi kwa kuondoa udongo na kuacha vishimo vidogovidogo.

Mmomonyoko mkubwa zaidi hutokea maeneo yenye mteremko mkali, hii ni kwasababu maji hukimbia kwa kasi zaidi hivyo kubeba udongo kirahisi. Udongo ulio momonyolewa kutoka maeneo zinakonyesha mvua (catchment areas), hubebwa na maji hadi kwenye mikondo mikubwa ya maji, mito na baadaye kwenye mabwawa na mikusanyiko mikubwa ya maji. Huko huyafanya maji kuwa na tope jingi (muddy/ turbid) na kuua mimea inayopatikana humo na viumbe wa majini. Hili likiendelea kwa miaka kadhaa, tope huchukua sehemu kubwa ya mabwawa na hivyo kupunguza kiwango cha maji yanayohifadhiwa na bwawa husika.

Ni vyema kuhakikisha miti na uoto juu ya aridhi (ground cover) vinalindwa na kujihakikishia uthabiti wa udongo wa juu (top soil) ili kupunguza nguvu ya matone ya mvua kuifikia aridhi moja kwa moja na kumomonyoa aridhi kiurahisi zaidi. Uoto pia hupunguza nguvu ya maji yanayokimbia juu ya aridhi hasa karibu na maeneo ya kuhifadhi maji hivyo kupunguza mmomonyoko.

Barabara zilizojengwa vibaya kwa kuwekewa miinuko mikali, huweza kuongeza kasi ya maji, na kama mitaro yake haijajengwa basi udongo mwingi utamomonyolewa na tope kupelekwa kwenye  maeneo ya kuhifadhi maji.. Barabara zikijengwa vizuri kwa kuzingatia maeneo maalumu ya kutokea  maji (drainage structures) uweza kupunguza kasi ya maji na hivyo kupunguza mmomonyoko wa udongo.

Mmomonyoko wa udongo hupelekea tope kujaa kwenye mabwawa ya kuhifadhia maji.

Moto na Ubora wa Maji

Je kuchoma moto maeneo ya misitu au vyanzo vya maji hupunguza ubora wa maji? Jibu ni NDIOOOOO!!!

Moto wa msituni mara nyingi huwa na nguvu sana, na wakati mwingine sio rahisi kuthibiti. Huathiri misitu, miji, maisha ya watu na mashamba. Mara nyingi aina ya moto huu watu huchoma maeneo ambayo hayajawahi kuchomwa kwa miaka mingi hivyo kuwa na kiwango kikubwa cha maganda, majani, miti iliyokufa na masalia ya uoto mchanganyiko ambavyo huwa ni kichochezi (ground fuel).

Baada ya moto kuunguza msitu, aridhi hubaki nyeusi na tupu. Kama baada ya moto itafuata mvua kunyesha, basi majivu yaliyotokana na moto yatachukuliwa na maji ya mvua kwenda kwenye mikondo mikubwa na baadaye kwenye hifadhi za maji. Pia ikiwa baada ya moto utafauata upepo mkali, basi utabeba mabaki ya uoto na majivu na kuyapeleka kwenye vyanzo vya maji. Na pia kama mvua kubwa itaendelea kunyesha kabla uoto haujaota tena (vegetation recovery) basi udongo utamomonyoka kirahisi na kubebwa hadi kwenye hifadhi za maji hivyo kuyachafua na kupunguza ubora wa maji.

Nini Tufanye sasa?

Natoa rai kwa watu wote tupige vita uharibifu wa misitu kwa:

Kutokata miti ovyo, bali kupanda miti mingi,

Kutochoma moto bila utaratibu na kuweka njia za moto ikiwa ni lazima kufanya hivyo,

Kutofanya kazi za uzalishaji kwenye maeneo ya vyanzo vya maji kama kulima, kufuga n.k

Kuhakikisha mikondo ya kutolea maji inajengwa kwa kufuata utaratibu hasa wakati wa ujenzi wa miundombinu ya barabara,

Kutunga sharia ndogondogo zitakazo wabana wanaokiuka sera ya taifa ya utunzaji mazingira na vyanzo vya maji.

Kupendelea kutumia nishati mbadala zisizo haribu mazingira.

Wakati wewe unachezea maji na kuharibu vyanzo na miundombinu yake, tambua wapo watu hawana maji kabisa.

Hitimisho:

Suala la kulinda vyanzo vya maji na utunzaji wa mazingira kwa ujumla halihitaji mtu awe msomi wa darasani ili kujua umuhimu wake. Hata wazee wa zamani hawakwenda shule lakini waliweka sheria kali na vitisho kwa watu wanaoharibu mazingira ili kuhakikisha wanalinda rasilimali hii muhimu. Hii ndio imesababisha tumeikuta misitu ya hifadhi kama Nyumbanitu uliopo mkoani Njombe, ambao umetunzwa kiasili kabisa tangu na wazee wa zamani, lakini umekuwa kivutio na chanzo muendelezo wa uzalianaji wa viumbe hai (ecosystem). Anza wewe kuyalinda mazingira, kumbuka maji ni uhai na bila maji hakuna linaloweza kufanyika.!

Eng Nguki Herman. M (Irrigation & Water Resources Engineering)

Email: ngukiherman@ymail.com

Instagram: @eng.ngukiwamalekela

Phone: 0763 639 101/ 0679 639 101

Marejeo: 

1.      Clark, S. 1988. Institutional and legal issues. In: Working Papers for the National Workshop on Integrated Catchment Management. University of Melbourne, 17-19 May, 1988.

2.      Commonwealth of Australia 2000. Co-ordinating Catchment Management: Report of the Inquiry into Catchment Management. House of Representatives Standing Committee on Environment and Heritage, Canberra.

Nakushukuru kwa kusoma katika blog hii ili kujipatia maarifa juu ya maji, kilimo na mazingira. Ukitaka kupata mada mbalimbali za kijamii, vijana na mahusiano, tembelea www.ngukiherman.blogspot.com

MVUKIZO KATIKA UHIFADHI MAJI (EVAPORATION)

Mvukizo/Evaporation-Upotevu wa maji usioonekana kwa macho. 

Mvukizo au Evaporation kwa kingereza ni hali ya maji kubadilika na kuwa katika maada ya gesi.. Ili hii kutokea ni lazima nishati nyingi na mgandamizo wa hewa uwepo, na ndio maana mvukizo huwa mkubwa kwenye maeneo yenye joto kali.. Mvukizo hurudisha sehemu ya maji iliyoshuka kama mvua moja kwa moja  katika angahewa (atmosphere) kabla hayajatumika kwa shughuli yoyote.

Mvukizo/Evaporation inatokea kuanzia muda mchache baada ya mvua kukatika hadi kwa kipindi cha msimu mzima (whole season). Kama ilivyo katika mvua, mvukizo pia hupimwa kwa kizio cha milimita chini ya muda fulani kwa kutumia kifaa kiitwacho Evaporation pan. Kivyovyote sehemu hii ya maji ya mvua hupotea bure. Japo kiasi cha maji haya kinachopotea huwa hakifahamiki na wapanga miundombinu wengi (infrastructure planners). Mfao angalia picha ya kwanza juu hapo, ni eneo la wazi bila hata miti pembeni wala uoto kitu ambacho ni kosa kubwa.

Mfumo wa mzunguko wa maji (Hydrological cycle)

Upotevu huu wa maji huwa kwa mfumo wa mvuke (water vapour), na mvuke hauonekani kwa macho ya kibinadamu (usiwaze ule mvuke kwenye sefuria unalopikia chakula baada ya kufunua mfuniko, la hasha fikiria eneo pana kama bwawa) hivyo huunda kiwango cha maji ambacho hupotea bila kujua  (unseen loss of water). Kutokana na hili, kiasi kikubwa cha maji hupotea katika mito,mabwawa, mitaro ya kugwia maji nakadharika.

Tazama mifano michache ya upotevu huu wa maji:

1.Fikiria eneo lenye ukubwa wa eneo 10KM², na mvukizo katika uso wa eneo (Evaporation in vicinity of the reservoir) 5mm/siku.

Kiasi cha maji kinachopotea kwa siku (vizio vimebadilishwa vyote kweme mita kwaajili ya uzidishaji)    

= 5x 10^-3 x 10 x 10⁶ M²

=50,000M³

Kiasi hiki cha maji (mita za mraba 50,000) zinatosha kuhudumia kijiji chenye makazi (households) 300 kwa matmizi ya nyumbani (domestic water supply) kwa miaka sita (Lakini kinapotea kwa siku moja)

Au tazama mfano wa pili:

Fikiria eneo lenye maji kwa ukubwa wa 2KM², na mvukizo katika uso wa eneo (Evaporation in vicinity of the reservoir) 5mm/siku.

Kiasi cha maji kinachopotea kwa siku (vizio vimebadilishwa vyote kweme mita kwaajili ya uzidishaji)    

= 5x 10^-3 x 2 x 10⁶ M²

=10,000M³

Kiasi hiki ch maji ni sawa na mvua au maji ya kumwagilia yenye kiwango cha milimita 100 kutumika katika shamba la hekta moja. Kwa lugha nyingine kiasi cha maji kinachopotea katika eneo la kuhifadhia lenye ukubwa wa kilometa mbili za eneo kwa siku moja kinatosha kutumika kumwagilia shamba lenye ukubwa wa hekta moja kwa mwaka mzima.

Kwa mifano hiyo miwili unaweza kupata picha ya haraka kiwango kikubwa cha maji kinachopotea kwa njia hii.

Nini kifanyike?

Mbinu za kupunguza upotevu huu wa maji zipo nyingi. Hapa nakutajia mbinu mbili rahisi kuzielewa

1. Kwanza ni kuhifadhi maji katika miundombinu yenye kina kirefu kuliko eneo la juu ( greater depth than surface area). Hii inapunguza eneo la maji linalofikiwa na jua na upepo hivyo kupunguza mvukizo.

1. Kupanda miti kuzunguka eneo ulilohifadhi maji kwa maana upepo pia huweza kuchangia mvukizo kwa kiwango fulani.

Kumbuka njia za upoteve wa maji katika mabwawa ziko nyingi na kila moja na njia yake ya kupunguza kwa maana sio rahisi kuthibiti kwa asilimia 100.

Tazama bwawa hili lilivyozungukwa na miti. Kwa njia hii mvukizo huwa kidogo sana na nirahisi kingo zake kutumika kama mazalia ya samaki na kuchochea uzalianaji wa ikolojia nyingine.

Nakupongeza kwa kujifunza na endapo unaswali juu ya mada hii waweza uliza kwa nia yoyote uipendayo. Like page yetu facebook pia (Water Droplet Community-WADCo Tanzania) kwa mada nyingine nyingi zinazohusu maji, umwagiliaji, udongo na mazingira. Naamini pia umeelewa kiswahili changu ambacho pengine baadhi ya maneno huwa rahisi kueleweka yakitumika kwa lugha ya kiingereza.

Eng Herman Nguki (Irrigation & Water Resources)

ngukiherman@ymail.com

0763 639 101/0679 639 101

Follow instagram @eng.ngukiwamalekela

Nakukumbusha kwa mada mbalimbali za vijana, jamii,mahusiano na imani tembelea www.ngukiherman.blogspot.com

MIGOGORO YA MAJI YAZIDI KUONGEZEKA

Ofisi za Bonde la Mto Pangani, mkoani Kilimanjaro, imekiri kuwapo kwa ongezeko kubwa la migogoro kati ya wakulima na wananchi wa kawaida inayosababishwa na uhaba wa maji.

Akizungumza na waandishi wa habari (5 Jan 2017), Ofisa wa Bonde hilo, Mtoi Kanyawana, alisema migogoro ya maji imekuwa ikiongezeka siku hadi siku kutokana na ukame kuyakumba baadhi ya maeneo nchini.

“Hadi sasa tumepokea malalamiko kutoka maeneo mbalimbali ikiwamo katika vijiji 19 vya Wilaya ya Moshi, mkoani hapa vyenye wakazi zaidi ya 56,000.

“Wananchi hao wanadai kukosa huduma ya maji ya kunywa na matumizi ya nyumbani kutokana na uwepo wa mradi wa kilimo cha umwagiliaji wa Kirua Kahe.

“Changamoto kubwa inayosababisha vyanzo vingi vya maji kuvamiwa na kuharibiwa vibaya na wananchi ni kutokana na kubadilika badilika kwa uongozi wa maeneo ya vijiji, hali ambayo inasababisha mfumo wa matumzi ya maji kubadilika.

“Hata hivyo, kwa sasa tupo katika mchakato wa kuainisha na kuyapandisha hadhi baadhi ya maeneo ya vyanzo vya maji na kuyahifadhi ili kuhakikisha vyanzo hivyo vinalindwa na tatizo la upungufu wa maji linakwisha,” alisema Kanyawana.

Kwa mujibu wa Kanyawana, maeneo yote ambayo yanategemewa kupandishwa hadhi na kuwa hifadhi, yatakuwa chini ya miliki ya bonde hilo na jukumu la kusimamia maeneo hayo wataliacha kwa Serikali za mitaa na vijiji kwa kushirikiana na jumuiya za watumia maji.

“Yapo maeneo ambayo ni vyanzo vya maji, tuna mpango wa kuja kuyatangaza ili yajulikane rasmi ili wananchi ikiwamo wafugaji ambao wataingia, waweze kuwajibishwa kisheria.

“Lakini pia, maeneo mengine ambayo yana vyanzo vya maji husimamiwa na jumuiya za watumia maji ambazo zipo kisheria,” alisema.

Pamoja na hayo, alisema suala la utunzaji wa mazingira katika vyanzo vya maji ni jambo muhimu na si jukumu la ofisi za Bonde la Mto Pangani peke yake.

Source// Mtanzania 6 Jan 2017

Bila maji hakuna watu. Hayana ladha lakini huishi tabasamu wakati wa kuyanywa.

Kwa sisi wadau wa rasilimali maji lazima tukubali kuwa hali hii inakoelekea inazidi kuwa mbaya. Nimechukua habari hiyo ya mfano kwa mkoa wa Kilimanjaro, lakini hali ni tete sehemu nyingi sana za nchi yetu. Hapa hatujikiti tu kulaumiana lakini upungufu wa maji maeneo mengi umetokana na uharibifu wa mazingira, uvamizi wa vyanzo vya maji kwa kilimo n.k. Kwa bahati mbaya wavamizi wa vyanzo vya maji wamekuwa wakifumbiwa macho ilihali wanafahamika, na huenda ni watu wenye ushawishi kwa jamii au nyadhifa fulani.

Lazima jicho la tatu litumike kuangalia tunakoenda. Mabadiliko ya tabia ya nchi ambayo nayo kwa kiwango kikubwa yamechagizwa na uharibifu wa mazingira yanatishia hali ya maisha ya kizazi kijacho. Ni kweli teknolojia nyingi zinazidi kuvumbuliwa ili kutumia nishati mbadala na rafiki kwa mazingira, lakini bado muamko wa jamii ni mdogo ama kutokana na ukosefu wa elimu, gharama za teknolojia au makusudi tu.

Hili lipo wazi na ndio maana ukienda baadhi ya maeneo ambako wametunza mazingira na wamejiwekea sheria kali za kuthibiti wahalibifu wa misitu na wavamizi wa vyanzo vya maji, hali ni nzuri sana kana kwamba wao sio wa nchi hii. Kumbe jamii sasa umefika wakati wa kubadilika na kuthamini mustakabali wa kizazi kijacho. Sio tu kuweka sheria, bali kuwa na ufuatiliaji wa karibu kuhakikisha hakuna anayekiuka. Bila maji hakunamaisha.

Eng Nguki Herman (Rasilimali maji na umwagiliaji)

0763 639 101/0679 639 101

ngukiherman@ymail.com

Asante kwa kutembelea blog yetu. Kwa maoni na ushauri au maswali usisite kutuandikia kupita mawasiliano yaliyopo au kwa njia ya comment. Karibu pia www.ngukiherman.blogspot.com kwa mada mbalimbali za viajana, ushauri , familia na maisha kwa ujumla.

The Basic Parts of a Drip System

Filter checkup at Igingilanyi Village drip system- Iringa

Illustration of a very simple drip system

Hellow, welcome to Water Droplet Community. To day I would like to present to you basic parts of Drip irrigation system with their general management. Simple language have been used to equip easy understanding . You are welcome.

Valves:

Valves turn on or off the water flow through a pipe.

Isolation valves are manually operated valves used for infrequent shut-off of the water. Typically an isolation valve is located at the water source so the water can be shut off for repairs or shut off during the non-irrigation season. Isolation valves may also be installed anywhere on the irrigation system to allow the shut down of sections for repair, this is common on large systems where shutting down the whole system for a repair would be inconvenient.

Control valves are the valves that turn on and off the water to individual “circuits” or areas of the yard that are irrigated separate from one another. The control valves can be automatic (usually electric-powered using a solenoid) or manually operated (hand-powered, ie; turn, turn, turn!) There may be just one control valve or there may be several control valves on a drip irrigation system. For example one control valve may turn on and off the water to emitters/drippers in a vegetable garden. Another control valve might turn on and off the water to emitters for some hanging pots on a patio. Another control valve might turn on and off the water for the emitters at shrubs around the house. Another could even turn on and off water for sprinklers in the lawn, or water for filling the swimming pool or pond. For more information on valves for drip systems, click here

Backflow Preventer:

The backflow preventer is a device that prevents dirt, salmonella, dog pee, etc. from being sucked back into your drinking water from the drip system. You need to use a backflow preventer on ALL drip systems. No exceptions! For more information on backflow preventers, why you need one, and a simple guide to which type to use, see the page on backflow preventers- click here

Pressure Regulators and Pressure Reducing Valves:

A pressure regulator reduces the water pressure and keeps it at a constant level. A pressure reducing valve is another name sometimes used for a pressure regulator, both are the same thing.Most drip systems operate best at lower water pressures than are common in a typical water supply system. A pressure regulator is used to lower the pressure and then keep it at that pressure, even if the incoming water pressure varies up and down. You probably will need to install a pressure regulator on your drip system if your water pressure is higher than 2,8 bars (40 PSI). Keep in mind that a pressure regulator only reduces the water pressure. It will never increase the water pressure, so if you don’t have enough water pressure a pressure regulator will cause you to have even less!

While the name sounds similar, a “back-pressure valve” is not a pressure regulator and has a different purpose.There are two general types of pressure regulators used, non-adjustable ones (with a factory pre-set outlet pressure) and ones with user adjustable pressure settings. Either type may be used for a drip system. As a general rule the non-adjustable type are used for small homeowner drip systems that utilize less than 3 control valves.

 Those people who want the best of everything, regardless of cost, would want to use the adjustable-type pressure regulators, as they allow more flexibility and are usually more accurate.Inexpensive, non-adjustable-type pressure regulators (see photo below) are most often used for simple home drip systems. They are typically made of plastic and have a pre-set outlet pressure. They often have very specific flow ranges and will not work if used at flows higher or lower than the listed range. Since they are not adjustable, be sure to buy the correct one for the flow and pressure your drip system needs.

 The non-adjustable-type regulators must be installed AFTER the control valve, so if you have more than one control valve you will also need one regulator for each of the control valves. If a valve is installed after a non-adjustable-type pressure regulator it can result in a pressure surge that can damage your drip system. It has been my experience that when used on systems where very high water pressures are present some of the non-adjustable-type regulators may allow a quick pressure surge to pass through just after the valve is opened. If you experience problems with drip tubing blowing out of the fittings right after the control valve is opened you may be experiencing this problem. Try switching to an adjustable-type pressure regulator.

Add cNon-adjustable-type pressure regulator.

(Install after control valve.)

Notice this regulator has pipe threads. See the section below on pipe vs. hose threads.aption

The classic adjustable-type pressure regulator can go before or after the control valve. This type of regulator is most often made of brass or bronze, (some plastic versions are made) and has a large screw on it that is used to adjust the outlet pressure. The adjustable-type pressureregulator you use needs to be the correct size as rated by the manufacturer for the flow range. Unfortunately the sizing formulas they provide are somewhat difficult to understand. As a general rule a 50mm (3/4″) adjustable-type pressure regulator will work acceptably for drip systems designed using the Drip Irrigation Guidelines on this website, provided the regulator is set to reduce the pressure by at least 1,4 bars (15 PSI). It is common for the pressure regulator to be a smaller size than the pipe it is installed on. Adjustable-type pressure regulators are often found in the plumbing department of hardware stores rather than with the irrigation supplies.The adjustable-type pressure regulators may be installed either before or after the control valves, whichever you prefer. On larger drip systems, with multiple control valves, the valves are often grouped together in one or more locations and a single adjustable-type pressure regulator is installed on the mainline before all of the valves in a group. This cost-saving measure allows a single pressure regulator to be used for several valves.

To operate accurately the adjustable-type pressure regulators require a pressure drop between the inlet and outlet of the regulator. The amount of pressure drop varies depending on flow, at low flows less drop is required. As a general rule most regulators will work well if you set the pressure at least 1,4 bars (15 PSI) lower than the inlet pressure. If the pressure drop is less than required, the regulator tends to not work as accurately, and may allow the pressure to vary up and down considerably.

Brass adjustable-type pressure regulator.
The large silver bolt on top is turned to change the outlet pressure

Using a Valve as a Pressure Regulator:

Can I reduce the pressure by partially opening the control valve and not use a pressure regulator? This is a common question, and the answer is yes, you can. If the water pressure from your water source does not fluctuate, and the temperature of the valve does not change, a partially closed valve will work just fine. A pressure regulator is nothing more than a valve with a pressure sensor attached to it. The sensor opens and closes an internal valve in the pressure regulator to keep the pressure at the outlet constant. So yes, you can use a partially closed valve to reduce the pressure, however you need to be aware of the problems this can cause. Sometimes the vibration of the water passing through the valve will cause the valve to open or close a little over time. The biggest problem occurs when the water is warmer or colder than the valve. 

The valve will change temperature as the water goes through it and expand or contract, this results in a change in how much water goes through the valve, and that changes the water pressure. If the valve closes due to vibration or temperature change the pressure may be reduced to the point the drip system stops working correctly and the plants don’t get watered. If the valve opens too far the water pressure will be too high. This results in emitters popping out of the tubes and tubing sections blowing apart at the fittings where they connect together. Often when the tubes blow apart they whip around, spraying water all over the place. The worst situation is when there is an open window nearby and the water sprays into the house through the window! So if you are willing to live with those risks, you can use a standard valve in place of a pressure regulator. All you do is open the valve slowly until the pressure desired is obtained downstream of the valve, then leave it at that setting. I suggest periodically checking the valve and water pressure to make sure it has not changed.

Filter:

The filter cleans the water. You should use a filter. Some companies tell you their products don’t need a filter when used with city water, or that it is optional. Optional at the expense of your future time and money! Save yourself dead plants and lots of grief and just install a filter. Drip emitters have very small openings that are easily clogged. Water piped to your house is not free from stuff that will clog your emitters! It contains small grains of sand, bits of rust and scale from pipes, even very small snails (the size of a grain of sand) are very common in city water systems.

I suggest that you use a filter with a 150 mesh screen or one with a higher mesh number like 200 mesh. A good quality filter may be installed before the valve or pressure regulator, but the inexpensive filters often sold for drip systems should be installed after the pressure regulator. A good filter will have a maximum pressure rating of 10,3 bars (150 PSI) or higher. If the package does not list the pressure rating it is probably an inexpensive low-pressure model.

I like to use a top quality filter and install it right at the water source so it protects the control valves and the pressure regulator too. Most valve failures result from sand or rust particles clogging the tiny passages inside the control valves! As long as you need to use a filter, why not get a good one and have it protect the valves too? It will probably pay for itself within 5 years by preventing a valve failure! Use a filter that is the same size as, or larger than, the valve. For more information there is a separate, free, tutorial on filters. Click here for the Filtration Tutorial.

Emitters:

The emitters are what controls how fast the water drips out onto the soil. Most emitters are small plastic devices that either screw or snap onto a drip tube or pipe. Some models are preassembled as part of a tube. The most common emitters sold emit 4 liters/hour (4,0 l/hr) of water. That’s about 1 gallon per hour (1 gph). There are many different types and brands available, they each have advantages and disadvantages listed in the detailed page on Drip Emitters. Click here for detailed information on what type of emitter is best for your drip system.

Drip Emitter on a tube
(If you guessed the plants are strawberries, you guessed correct!)

Mainline:

The mainline is the pipe that goes from the water source to the control valves. In the illustration of a very simple drip system above the gray colored vertical pipe under the valve is a very short mainline. The mainline pipe may be made of galvanized steel, copper, SCH 40 PVC, SCH 80 PVC, Cl 315 PVC, Heavy Wall Polyethylene (SDR 7 or SDR 9) or PEX. PVC is damaged by sunlight and should be buried or protected. Apply several heavy coats of paint or wrapping PVC with aluminum tape if it is above ground. Polyethylene has a low burst pressure and should only be used for mainlines where local conditions are appropriate and water pressures are lower than 3,5 bars (50 PSI). PEX pipe is a special type of polyethylene made for use with higher pressure, often sold as a replacement for copper tube. It may be used for a mainline, however, be aware that due to a much smaller inside diameter it has poor flow qualities when compared to copper. I recommend that when using PEX you use one tubing size larger than you would use for copper tube. 

On large drip systems a single mainline might lead to several control valves located at different areas of a yard. On large properties a mainline will be install in a loop around the perimeter of the property. Because the water in the mainline is always pressurized, hose bibs are often installed on the mainline. On a large property with a looped mainline hose bibs are often installed on the mainline at 30m intervals (100 feet) around the property to allow for use of hoses. I like to foliar fertilize my plants using liquid fertilizer from a hose-end applicator, and the hose bibs make this easy. 

There are also devices called “quick coupler valves” that are essentially a water outlet that is mostly underground. You plug a special coupler with a hose attached to it into the quick coupler valve. They are typically only available from on-line retailers or local irrigation specialty stores. I use them in most of my commercial irrigation systems, the maintenance folks love them.

Lateral and/or Sub-Main:

The lateral is the pipe located between a control valve and the drip tube. Some people use the name “sub-main” for this same pipe. I used the term sub-main in the first version of these guidelines, but have decided to use lateral now to avoid confusion with the names used for sprinkler systems. The lateral pipe may be PVC, PEX, or polyethylene. The lateral is located after (downstream) of the pressure regulator so it is not necessary to use a pipe with a high pressure rating. Class 200 PVC or standard “polyethylene irrigation pipe” work good for laterals. Class 125 PVC may also be used but be careful as it breaks easily. PVC is damaged by sunlight and should be buried or protected. Apply several heavy coats of paint or wrapping PVC with aluminum tape if it is above ground. Many small drip systems do not have laterals, in those systems the drip tube connects directly to the control valve. 

The illustration of a very simple drip system at the top of this page shows a system without a lateral. Laterals are often used when multiple drip tubes are needed, such as when the irrigated area is too large for a single drip tube. For example a single lateral or multiple laterals might extend from a single control valve to several drip tubes located in different areas of a yard.

Hose Threads vs. Pipe Threads:

Two different thread types are typically found on 3/4″ drip equipment. Hose threads are the type of threads found on garden faucets and garden hoses. The female side will have a soft hose washer in it to seal the connection. Typically they also have a swivel device on the female side, but not always. Pipe threads are the type of threads found on standard pipes. It’s really confusing, unfortunately, and it is not easy for someone without experience to just look at the threads and tell them apart!

How to identify hose threads: If there is a washer inside a 3/4″ female fitting that is a pretty good sign it is a hose thread. (Although there are some specialty fittings that use washers and have pipe threads. For example; sink water supply hoses.) When looking at male threads, hose threads have threads that are slightly larger and are farther apart from each other. 

There also tend to be a smaller number of threads when hose threads are used and the threaded section of the fitting tends to be shorter. (See photo below.) If you look at male pipe threads you will notice there is a slight taper to the threaded area, the end has a slightly smaller diameter than the back (look real close at the male threads on the left side in the photo below, you can see the diameter increases slightly as you move toward the right.) This works a bit like a tapered cork for a bottle. The taper forces the male pipe threads to bite into the female pipe threads, helping seal the joint as you tighten the connection.

Connecting hose threads to pipe threads: It is best to use a special adapter made to connect them. When you try to connect hose threads directly to pipe threads, it will start out fine and will seem like they fit. But once you get past a couple of full turns you will feel considerable resistance because the threads don’t match. Sometimes with plastic fittings they can be forced together, but most often if you do this the connection will leak (if you force them together there is a good chance of causing unrepairable damage!) A trick that sometimes works for a quick fix when connecting a hose thread to a pipe thread is to put two washers in the joint rather than one. A much better way is to use a special adapter made for the conversion (see photos of adapters below.)

Hose to pipe adapters: They make adapters that have hose threads on one side and pipe threads on the other. They are available in many combinations: male hose to male pipe, female hose to female pipe, as well as male to female versions. There are also versions that convert to 1/2″ pipe threads rather than 3/4″. Any good hardware store should have at least a couple of these combinations available. A good suggestion is to “mock up” your connections by screwing them together slightly in the hardware store before you buy the parts. That way you know they will fit. To help you read labels, common abbreviations used in hardware stores are

•     MHT = Male Hose Thread
•      FHT = Female Host Thread
•      MPT = Male Pipe Thread
•    FPT = Female Pipe Thread
•    Pipe = Pipe Thread
•   Hose = Hose Thread.                                                                                                                                                                                                                                                                 Remember to use Teflon tape sealer on male pipe threads to prevent leaks. Avoid liquid pipe thread sealants on irrigation systems, excess sealant breaks loose inside the pipe and clogs the emitters and sprinklers. You don’t need Teflon tape on hose thread connections, they should have a hose washer that seals them.

Pipe Thread to Hose Thread Adapters
Pipe threads are on left, hose threads on right
Top is a MPT x MHT adapter, bottom is a FPT x FHT adapter

Drip Tubing (Drip Hose):

Drip tubing is a special tube used in most drip systems. The tube is laid on the ground surface between the plants. The emitters are installed on this drip tube. Drip tubing is a thin-wall polyethylene tube (thinner than standard polyethylene hose), has a low pressure rating, and is generally produced in metric sizes. Sometimes it is called drip hose or drip pipe. Common sizes are 12 mm (0.455″ or 3/8″), 16mm (0.620″ or 1/2″), 18mm (0.720″ or 1/2″), and 24mm (0.940″ or 3/4″). Do you see the problem? Two sizes are commonly referred to as “1/2 inch” in the USA! The fittings for these two are not interchangeable. So make sure you know what you’re getting when you buy it! Do not bury drip tubing underground- gophers and moles love to chew on buried drip tubing! Some drip systems do not use drip tubing. 

These systems are commonly called “hard-piped drip systems” and are used mostly for very high quality drip systems in commercial landscapes. On a hard piped drip system the emitters are installed directly onto the laterals. This requires special emitters with threaded connections rather than barbs. For a drawing showing how a hard piped emitter works click here.

Drip Tube Fittings:                                                                                    

Fittings (including tees, couplings, ells, and adapters) are the plastic connectors used to attach the drip tube to other tubes, to control valves, or to pipes. Important- make sure the fittings are the exact right size! Using fittings made for a different tubing size will result in the tube blowing out of the fitting. 9 times out of 10, when a tube blows out of a fitting it is because the fitting is the wrong size. If you use a 15mm fitting on 16mm pipe you are going to have problems. Remember, both 15mm and 16mm tube are often labeled as 1/2 inch size in the USA!

Barb type fittings insert into the drip tube. Generally they should not require the use of a hose clamp to hold them on, if a clamp is needed the water pressure is too high or the fitting is the wrong size. The advantage of barb fitting is that they are generally easier to install than the compression type. The disadvantage of the barb type is that as the tube goes over the barb it is stretched, which weakens the tube. The weakened tube will sometimes split open at the barb after a few years, especially if exposed to sunlight. OK you ask, if barbs are a problem then why do they use barbed fittings with standard polyethylene pipe? Standard poly pipe has a much thicker wall than drip tube and doesn’t stress as much when stretched. 

You also clamp standard poly pipe to the fittings, which helps keep the pipe from splitting (that’s why you need to clamp poly pipe even if it seems to stay in place without the clamps). Drip tubing is not clamped to the fittings (clamping doesn’t help prevent splitting because of the thin drip tubing wall).

Compression type fittings are basically the reverse of a barb fitting. The tube slides inside the fitting, where an internal barb compresses the tube and holds it in place. The advantage of compression fittings is that they do not stretch the tubing, so they are not a cause of premature failure of the tube. Once the tubing is inside a compression type fitting it is very difficult to remove.As a general rule, barb fittings are best used for buried or covered tubing (the tube is not exposed to sunlight) and compression fittings are used for tubing that is not buried.

Drip Tube Fittings
Left: Barbed Type Right: Compression Type

Lubrication: Some people just don’t have the strength to shove the tubing into a compression fitting. First make sure the fitting is the right size, as that is very often the problem. If it is, then you can use a water soluble lubricant on the tube. Do not use oil, silicon sprays (WD-40) or soap! Absolutely do not heat the tube with a flame, hair dryer, or hot water as that will stretch the tubing and create weak spots! What’s a water soluble lubricant? Try a product called K-Y Jelly. Attention guys! Avoid terminal embarrassment! Do not head for the hardware store for K-Y Jelly. Try the drug store, err, lady’s personal hygiene department. Might want to take along the wife. Need I say more?

Spaghetti, Feeder, and/or Distribution Tubing

Feeder Tubes, Spaghetti Tube, and Distribution Tubing are all names used for small diameter poly or vinyl tubes, anything less than 10mm (3/8 inch) in diameter. I love spaghetti to eat, but I hate it for use in drip systems! The problem with these small tubes is with maintenance. These little tubes tend to be easily cut, broken, pulled loose, etc. and are generally a nuisance. This small tube is often connected to the outlets of multiple-outlet emitters. This tubing is the reason I do not recommend the use of multiple-outlet emitters. 

If you are a meticulous type person who can be very careful, do your own yard maintenance, and you don’t have pets or kids in the yard, you may not have any problems. But for most of us, regret soon sets in as repairing these small tubes becomes a weekly maintenance chore. There are a couple of exceptions where the tubes work well. One is when they are stapled above ground to a trellis or arbor for watering hanging plants. They need to be firmly attached, in a location where they will not be damaged. The other is for risers used on hard-piped drip systems.

Air Vent:

The purpose of an air vent is to prevent air from being sucked into the emitters when the system is turned off. When the drip system is turned off the water in the pipes drains down to the lowest point, where it drains out of the emitters. As the water drains out it is replaced with air that is sucked into the tube through the higher emitters. As the air is sucked in, dirt may also be sucked in with it. The dirt may then get stuck and clog the emitter outlet. The purpose of the air vent is to allow air to be sucked in through the vent rather than the emitter. 

When used, the air vent is installed at the highest point on the drip tube. It is important to make sure that the air vent will not become covered with dirt or dirty water as that would allow dirt to be sucked into it. Always use air vents if the drip system is installed on a slope, as the elevation change creates a more powerful suction that will suck in more dirt. Air vents often are not used on smaller drip systems. If you don’t use them just make sure the highest emitters aren’t sitting where dirt can easily be sucked into them.

A small air vent designed for a drip system

Flush Valve or End Cap:

The end cap is important. Without it the water all runs out the end of the drip tube. (Well, duhhh…) The water in a drip system flows very slowly in the tubes. This allows any sediment in the water to settle out, over time a layer of this sediment develops inside the tube and needs to be flushed out. In some climates algae may also grow in the tubes and need to be flushed out periodically. Normally drip tubes are flushed once a year. If you have algae problems you may need to flush the tubes more often.

 Automatic flush valves are available that flush the tubing each time the water is turned on. I do not feel that most of these are particularly effective. They simply do not flush for long enough or flush enough water out to remove much, if any, sediment or algae. My preference is to use a manual flush valve, or just use a simple hose-thread cap that you can remove to flush the tube. Here’s a money saving tip; you can make a end cap/manual flush valve by just bending over the end of the drip tubing on itself to crimp off the flow. Then use some wire or a cable/zip tie to hold the tube in the crimped position. Un-crimp and straighten the tube when you want to flush it.

Tubing end crimped with a cable tie

For very high end drip systems with lots of algae or sediment you may want to build your own auto flush unit. This is an expensive project requiring a high level of skill and knowledge! Manifold the ends of the drip lines together, so that a single flush outlet can flush the entire drip circuit. Install a anti-contamination type solenoid valve as the flush valve on the end of the flush manifold. (An anti-contamination valve is a special irrigation valve made for use with dirtier than normal water.) Wire the flush valve to an irrigation controller and program it to open the flush valve on a periodic basis, typical might be for 2 minutes once a week. The drip circuit control valve must also be on during the flushing. So both the control valve AND the flush valve must be activated at the same time.

 Do not wire them together on the same controller circuit as that will cause the flush valve to remain open all the time. You will either need to use two controllers and then coordinate the times on them, or you will need a controller that can run two valves on two different programs at the SAME TIME. Warning; most irrigation controllers can’t do this. I suggest you take these instructions and go to a professional irrigation dealer and have them assist you in your controller selection. Make sure you have someplace for the flush water to go, as it will release a lot of waste water when the flush valve opens. Keep in mind that both anti-contamination valves and the special controller you need to use are expensive and this is not a very cost effective solution in most cases.

Drip laterals for onion nursery -Igingilanyi village, Iringa

Drip lateral foe Chinese cabbage, Igingilanyi village-Iringa

Eng Herman Nguki wa Malekela, (Irrigation & Water Resources)

ngukiherman@ymail.com

0763 639 101/0679 639 101

@Water Droplet Community (WaDCo Tanzania)

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